May 2026 - dovecot - dovecot.org

Problem with authentication in dovecot
by Freek de Kruijf 22 May '26

22 May '26

I have the following dovecot.conf, striped from comment: dovecot_config_version = 2.4.2 dovecot_storage_version = 2.4.0 protocols = imap auth_allow_cleartext = yes auth_mechanisms = plain auth_verbose = yes mail_plugin_dir = /usr/lib64/dovecot/modules namespace inbox { inbox = yes mail_driver = maildir mail_path = ~/Maildir prefix = INBOX. mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Trash { auto = subscribe special_use = \Trash } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } } passdb pam { service_name = dovecot } userdb passwd { use_worker = yes } service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0666 user = postfix } } ssl = yes ssl_server { cert_file = /etc/letsencrypt/live/<mydomain>/fullchain.pem dh_file = /etc/dovecot/dh.pem key_file = /etc/letsencrypt/live/<mydomain>/privkey.pem } sieve_script personal { active_path = ~/.dovecot.sieve driver = file path = ~/sieve } When connecting my email client to dovecot, the connection succeeds, but after awhile it disconnects. In /var/log/dovecot I get: May 18 17:36:15 imap-login: Warning: Auth process not responding, delayed sending initial response (greeting): user=<>, rip=192.168.178.6, lip=192.168.178.15, session=<2IMbUhlS8K3AqLIG> May 18 17:36:45 imap-login: Info: Login aborted: Connection closed (disconnected before auth was ready, waited 40 secs) (auth_process_not_ready): user=<>, rip=192.168.178.6, lip=192.168.178.15, session=<2IMbUhlS8K3AqLIG> May 18 17:36:45 imap-login: Error: auth-client: conn unix:login: connect(login) in directory / failed: Permission denied (euid=473(<getpwuid() error>) egid=473(<getgrgid() error>) missing +x perm: /, we're not in group 474, dir owned by 0:474 mode=0750) May 18 17:36:45 imap-login: Error: auth-client: conn unix:login: connect(login) in directory / failed: Permission denied (euid=473(<getpwuid() error>) egid=473(<getgrgid() error>) missing +x perm: /, we're not in group 474, dir owned by 0:474 mode=0750) 473 is connected with account/group dovenull an 474 is connected with account/group dovecot I can't find a solution when searching the internet. -- fr.gr. member openSUSE Freek de Kruijf I have the following dovecot.conf, striped from comment: dovecot_config_version = 2.4.2 dovecot_storage_version = 2.4.0 protocols = imap auth_allow_cleartext = yes auth_mechanisms = plain auth_verbose = yes mail_plugin_dir = /usr/lib64/dovecot/modules namespace inbox { inbox = yes mail_driver = maildir mail_path = ~/Maildir prefix = INBOX. mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Trash { auto = subscribe special_use = \Trash } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } } passdb pam { service_name = dovecot } userdb passwd { use_worker = yes } service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0666 user = postfix } } ssl = yes ssl_server { cert_file = /etc/letsencrypt/live/<mydomain>/fullchain.pem dh_file = /etc/dovecot/dh.pem key_file = /etc/letsencrypt/live/<mydomain>/privkey.pem } sieve_script personal { active_path = ~/.dovecot.sieve driver = file path = ~/sieve } When connecting my email client to dovecot, the connection succeeds, but after awhile it disconnects. In /var/log/dovecot I get: May 18 17:36:15 imap-login: Warning: Auth process not responding, delayed sending initial response (greeting): user=<>, rip=192.168.178.6, lip=192.168.178.15, session=<2IMbUhlS8K3AqLIG> May 18 17:36:45 imap-login: Info: Login aborted: Connection closed (disconnected before auth was ready, waited 40 secs) (auth_process_not_ready): user=<>, rip=192.168.178.6, lip=192.168.178.15, session=<2IMbUhlS8K3AqLIG> May 18 17:36:45 imap-login: Error: auth-client: conn unix:login: connect(login) in directory / failed: Permission denied (euid=473(<getpwuid() error>) egid=473(<getgrgid() error>) missing +x perm: /, we're not in group 474, dir owned by 0:474 mode=0750) May 18 17:36:45 imap-login: Error: auth-client: conn unix:login: connect(login) in directory / failed: Permission denied (euid=473(<getpwuid() error>) egid=473(<getgrgid() error>) missing +x perm: /, we're not in group 474, dir owned by 0:474 mode=0750) 473 is connected with account/group dovenull an 474 is connected with account/group dovecot I can't find a solution when searching the internet. -- fr.gr. member openSUSE Freek de Kruijf

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Regression/Bug report: crypt_private_key_file (for crypt_global_private_key) no longer supports inline base64 (from userdb) in dev branch
by Ömer Güven 22 May '26

22 May '26

Hi, I’ve run into what appears to be a regression (or at least a behavioral change) in Dovecot 3.3.0+ / current HEAD regarding crypt_private_key_file handling for the crypt_global_private_key. I don‘t use per-folder user keys but a global encryption key per user. Previously, it was possible to provide the private key via userdb using an inline base64:-encoded PEM directly to the crypt_global_private_key_file and Dovecot would correctly parse and use it. With the latest config scheme change, this no longer works, as you cannot really set named config variables from userdb. I did workaround by setting a custom userdb variable and setting the needed named/filter variables manually in the config file. To make it work, I had to enclose the config in a „protocol imap“ scope. The crypt_global_public_key_file is accessible from userdb (as it is not within a named filter scope), so inline-base64 works as with Dovecot 2.3+. When using the following workaround to reach the scoped variables, Dovecot tries to load the file „inline:BASE64ENCODEDPEM“ as a literal filename (error open(inline:AB….C==) failed): protocol imap { crypt_global_private_key user { crypt_private_key_file = %{userdb:private_key_file} crypt_private_key_password = %{userdb:private_key_password} } } As a workaround, I now have to: • store the private key as a file (e.g. %{home}/privkey.pem) • pass only the password via userdb • inject the path indirectly via static config + userdb variables This works, but is less elegant: protocol imap { crypt_global_private_key user { crypt_private_key_file = %{home}/privkey.pem crypt_private_key_password = %{userdb:private_key_password} } } Again, with the new named filter mechanism, it’s no longer possible to directly inject such config values via userdb, which makes fully dynamic per-user key provisioning harder. I now have to export all encrypted private keys from the database to the users home directory. Ömer Hi, I've run into what appears to be a regression (or at least a behavioral change) in Dovecot 3.3.0+ / current HEAD regarding crypt_private_key_file handling for the crypt_global_private_key. I don`t use per-folder user keys but a global encryption key per user. Previously, it was possible to provide the private key via userdb using an inline base64:-encoded PEM directly to the crypt_global_private_key_file and Dovecot would correctly parse and use it. With the latest config scheme change, this no longer works, as you cannot really set named config variables from userdb. I did workaround by setting a custom userdb variable and setting the needed named/filter variables manually in the config file. To make it work, I had to enclose the config in a "protocol imap" scope. The crypt_global_public_key_file is accessible from userdb (as it is not within a named filter scope), so inline-base64 works as with Dovecot 2.3+. When using the following workaround to reach the scoped variables, Dovecot tries to load the file "inline:BASE64ENCODEDPEM" as a literal filename (error open(inline:AB....C==) failed): protocol imap { crypt_global_private_key user { crypt_private_key_file = %{userdb:private_key_file} crypt_private_key_password = %{userdb:private_key_password} } } As a workaround, I now have to: o store the private key as a file (e.g. %{home}/privkey.pem) o pass only the password via userdb o inject the path indirectly via static config + userdb variables This works, but is less elegant: protocol imap { crypt_global_private_key user { crypt_private_key_file = %{home}/privkey.pem crypt_private_key_password = %{userdb:private_key_password} } } Again, with the new named filter mechanism, it's no longer possible to directly inject such config values via userdb, which makes fully dynamic per-user key provisioning harder. I now have to export all encrypted private keys from the database to the users home directory. Oemer

4 11

warning: /usr/lib/postfix/sbin/virtual: bad command startup -- throttling
by David Koski 22 May '26

22 May '26

Hello, I have set up a new dovecot mail server using MySQL backend. All users, passwords and related data are in SQL. I'm seeing the following warning in the mail.log file: warning: /usr/lib/postfix/sbin/virtual: bad command startup -- throttling It appears to have no impact on mail delivery. Since paths to user directories are yielded by the SQL database, I'm left wondering why this is even a warning. Regards, David Koski dkoski(a)sutinen.com # 2.4.1-4 (7d8c0e5759): /etc/dovecot/dovecot.conf # Pigeonhole version 2.4.1-4 (0a86619f) # OS: Linux 6.12.69+deb13-amd64 x86_64 Debian 13.5 # Hostname: B914839.online-server.cloud # 4 default setting changes since version 2.4.0 dovecot_config_version = 2.4.0 auth_debug = yes auth_debug_passwords = yes auth_mechanisms = plain login gssapi cram-md5 digest-md5 debug_log_path = /var/log/dovecot/debug.log default_vsz_limit = 512M dovecot_storage_version = 2.4.0 fts_autoindex = yes fts_autoindex_max_recent_msgs = 999 fts_search_add_missing = yes info_log_path = /var/log/dovecot/info.log lda_mailbox_autocreate = yes lda_mailbox_autosubscribe = yes log_debug = category=auth log_path = /var/log/dovecot/dovecot.log mail_driver = maildir mail_plugins { quota = yes } mailbox_directory_name_legacy = no protocols { imap = yes lmtp = yes sieve = yes } quota_exceeded_message = User %{user} has exceeded the storage volume. / User %{user} has exhausted allowed storage space. sieve_plugins { sieve_imapsieve = yes sieve_extprograms = yes } sql_driver = mysql ssl = required namespace inbox { inbox = yes prefix = separator = . type = private mailbox Drafts { auto = subscribe special_use = "\\Drafts" } mailbox Outbox { special_use = "\\Drafts" } mailbox Junk { auto = subscribe special_use = "\\Junk" } mailbox "Junk Email" { auto = no special_use = "\\Junk" } mailbox "Junk E-mail" { auto = no special_use = "\\Junk" } mailbox Trash { auto = subscribe special_use = "\\Trash" } mailbox "Deleted Items" { auto = no special_use = "\\Trash" } mailbox Spam { auto = no special_use = "\\Junk" } mailbox Archives { auto = no special_use = "\\Archive" } mailbox Sent { auto = subscribe special_use = "\\Sent" } mailbox "Sent Items" { auto = no special_use = "\\Sent" } mailbox "Sent Messages" { auto = no special_use = "\\Sent" } } service imap-login { inet_listener imap { } inet_listener imaps { } } service pop3-login { inet_listener pop3 { } inet_listener pop3s { } } service submission-login { inet_listener submission { } inet_listener submissions { } } service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { group = postfix mode = 0600 user = postfix } } service imap { } service pop3 { } service submission { } service auth { unix_listener auth-userdb { group = postfix } unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } } service auth-worker { } service dict { unix_listener dict { } } ssl_server { cert_file = /etc/letsencrypt/live/mail.sutinen.com/fullchain.pem key_file = /etc/letsencrypt/live/mail.sutinen.com/privkey.pem } protocol lda { mail_plugins { sieve = yes quota = yes } } protocol imap { mail_plugins { imap_sieve = yes } } protocol lmtp { mail_plugins { quota = yes sieve = yes notify = yes push_notification = yes } postmaster_address = postmaster(a)sutinen.com } service managesieve-login { inet_listener sieve { port = 4190 } inet_listener sieve_deprecated { port = 2000 } } service managesieve { } sieve_script personal { active_path = /var/vmail/sieve/%{user | domain }/%{user | username }/active-script.sieve driver = file path = /var/vmail/sieve/%{user | domain }/%{user | username }/scripts type = personal } sieve_script spam-global { path = /var/vmail/sieve/global/spam-global.sieve type = before } mailbox Spam { sieve_script spam { cause = copy path = /var/vmail/sieve/global/learn-spam.sieve type = before } } imapsieve_from Spam { sieve_script ham { cause = copy path = /var/vmail/sieve/global/learn-ham.sieve type = before } } mysql /var/run/mysqld/mysqld.sock { dbname = vmail password = # hidden, use -P to show it user = vmail } passdb sql { driver = sql query = CALL password_query('%{user}', '%{password}') } userdb sql { driver = sql query = CALL user_query_dovecot('%{user | username}', '%{user | domain}') }

3 2

Dovecot 2.4 authentication
by David Koski 22 May '26

22 May '26

Hello, I just put a new Postfix with Dovecot 2.4 server on line migrating the email from Dovecot 2.3. I have discovered a number of clients (all copiers so far) that no longer authenticate SMTP. Mechanisms configured: auth_mechanisms = plain login gssapi cram-md5 digest-md5 I found that if I disable all encrypted password methods (some copiers list them separately with a checkbox) and leave only plain/login on the client side, then it succeeds. But sometimes it is not necessary. It's almost as if it only tries once and gives up if it fails. I'm not sure how it is actually supposed to work. But it worked with Dovecot 2.3. I did test one account with an encrypted password like "{CRAM-MD5}6e3..." successfully. But other accounts failed. It almost looks like the encryption method must be specified on the client side to match the server before it will work consistently. I know that password encryption is unnecessary with STARTTLS but I have to live with it now. I have noticed that Thunderbird configured with encryption silently falls back to plain/login so I didn't notice a problem. Regards, David Koski dkoski(a)sutinen.com

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dovecot 2.4 Restricting Access - journal/log differences for failed login?
by David C Rankin 21 May '26

21 May '26

All, I have restricted access for several users using the Restring Access documentation https://doc.dovecot.org/2.4.0/howto/restrict_access.html This was to cut down on the brute-force attempts against dovecot for certain users whose usernames/e-mails are routinely used. I have a very simply passdb config: passdb passwd-file { passwd_file_path = /etc/dovecot/deny.%{protocol} deny = yes } passdb pam { driver = pam } userdb pam { driver = passwd } I created the /etc/dovecot/deny.imap file with one username per-line. But what confuses me is the server logs the exact same failure for unsuccessful login after restricting access as it did before restricting access. E.g. 2026-05-20T07:22:43.039585-05:00 valkyrie auth[28618]: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=janice(a)mydomain.com rhost=70.186.179.37 2026-05-20T07:22:51.578711-05:00 valkyrie auth[28618]: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=janice(a)mydomain.com rhost=70.186.179.37 May 20 07:25:36 valkyrie dovecot[1015]: imap-login: Login aborted: Inactivity (auth failed, 2 attempts in 177 secs) (auth_failed): user=<janice(a)mydomain.com>, method=PLAIN, rip=70.186.179.37, lip=192.168.6.14, TLS, session=<ouXP2T5SJpZGurMl> Is this normal, or should dovecot respond to restricted users in some way that differs from a normal login failure? All could be working fine, I'm just not certain about the log entries. -- David C. Rankin, J.D.,P.E.

1 0

"imap" command not usable in dovecot 2.4
by Mark Hills 20 May '26

20 May '26

Since upgrading to 2.4 (from 2.3) the "imap" command no longer works: $ /usr/libexec/dovecot/imap * PREAUTH [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE REPLACE SNIPPET=FUZZY PREVIEW=FUZZY PREVIEW SPECIAL-USE STATUS=SIZE SAVEDATE COMPRESS=DEFLATE INPROGRESS NOTIFY LITERAL+] Logged in as mark imap(mark)<6109><5GlNEEHaDWrdFwAABxE9Dg>: Fatal: Namespace inbox: mail_storage settings: Failed to parse configuration: Invalid setting mail_path=~/Maildir: mail_path setting used home directory (~/) but there is no mail_home and userdb didn't return it Whereas I would expect an authenticated IMAP session. Removing the offending /etc/dovecot.conf line temporarily: dovecot_config_version = 2.4.1 dovecot_storage_version = 2.4.0 protocols = imap lmtp sieve mail_driver = maildir #mail_path = ~/Maildir passdb passwd-file { passwd_file_path = /etc/dovecot/passwd } userdb passwd { } [...] And re-testing suggests the cause runs deeper: $ /usr/lib/exec/dovecot/imap [...] imap(mark)<6364><tetIC6/aDWrcGAAABxE9Dg>: Fatal: Namespace inbox: mail_storage settings: Failed to parse configuration: Failed to expand mail_path setting variables: Setting used home directory (%h) but there is no mail_home and userdb didn't return it Attempts to hard-wire it seem to suggest that usedb is not involved. I imagine this may be not consulted, because the process is pre-authenticated and running as a local UID: userdb passwd { fields_import_all = no fields { mail_home = /home/mark mail_path = /home/mark/Maildir } } $ /usr/libexec/dovecot/imap [...] imap(mark)<6656><qPqUB17cDWoAGgAABxE9Dg>: Fatal: Namespace inbox: mail_storage settings: Failed to parse configuration: Failed to expand mail_path setting variables: Setting used home directory (%h) but there is no mail_home and userdb didn't return it It seems like 2.3 looked up these fields from the user invoking it, but no longer is this the case? Running "imap" like this is very useful, especially when a client like Pine/Alpine can access over SSH. To get to here I had to workaround the missing "shadow" passdb module, which is also useful as Alpine Linux 3.23 neither uses PAM extensively nor provides dovecot built with PAM. -- Mark

1 0

undocumented changed behavior of 2.4.3 (possible bug report)
by Patrick Cernko 20 May '26

20 May '26

Hello Dovecot-Devs, hello list, while upgrading my Dovecot 2.4.2 setup to 2.4.3 I observed two instances of changed behavior. I could not find notes about those issues in the corresponding documentation (https://doc.dovecot.org/2.4.3/installation/upgrade/2.4-to-2.4.x.html) or release notes: 1. I had to change userdb_ldap_iterate_filter = (&(objectClass=posixAccount)%{if(protocol,"eq","pop3","(istIsMemberOf=POP3-users)","")}) to userdb_ldap_iterate_filter = (&(objectClass=posixAccount)%{if(protocol,"eq","pop3","(istIsMemberOf=POP3-users)","")|safe) otherwise the characters '()=' in the "true"-case of the condition got somehow "quoted" with escaped ASCII codes, which led to a broken LDAP filter string. Maybe you could add some documentation (in "Upgrading" as well as "Settings Variables") about that? 2. The behavior of sieve matches using ":matches" has changed: Example email (only the relevant header): List-Id: Dovecot Mailing List <dovecot.dovecot.org> Example Sieve script: if header :matches "List-Id" "*<dovecot*.dovecot.org>" { fileinto "dovecot"; } In 2.4.2 (and earlier) the example email matched the condition and got stored in the dovecot folder, while in 2.4.3 the condition does NOT match. As a workaround I added a '*' at the end of the match ("*<dovecot*.dovecot.org>*") to get my mails stored correctly again. Is this changed behavior for Sieve intentional or a bug? In case of a bug, could you please provide a fix? In case of intentional behavior: * Could you please explain the intention? Why was it necessary? * What would be the correct fix for the sieve example to match a List-Id header that ENDS WITH ".dovecot.org>"? * I assume, that other users on my servers will run into similar problems once I upgrade their servers. Is it possible to detect such problematic matches in Sieve scripts? E.g. "all matches without a trailing '*' are affected", ... This would give me a chance, to inform my users or even fix their scripts in advance. Best regards, -- Patrick Cernko <pcernko(a)mpi-klsb.mpg.de> +49 681 9325 5815 Joint Scientific IT and Technical Service Max-Planck-Institute für Informatik & Softwaresysteme

2 3

NFC normalization rename errors after 2.3 to 2.4 upgrade (mdbox)
by Jan Münnich 20 May '26

20 May '26

Hi, We just upgraded from 2.3 to 2.4.3 and are now getting errors like this for any mailbox with German umlauts in the name: "Error: Failed to rename mailbox 'Anträge' for NFC normalization: Mailbox doesn't exist: Anträge" The mailboxes work fine otherwise, doveadm mailbox status shows them with correct message counts. The errors show up on IMAP access but don't seem to break anything. We're using mdbox. On disk the directory is stored as mUTF-7: Antr&AOQ-ge doveadm mailbox list gives back the name with c3 a4 for the ä, which is already NFC. We double-checked with python3 unicodedata and it confirms the name is NFC. So it seems like dovecot is trying to rename something that doesn't need renaming, and then failing. Is there a way to turn off this automatic rename? Or is this a known issue with mdbox and mUTF-7 directory names? Any help would be appreciated to find out if this is a bug or a configuration issue on our side! Thanks, Jan

4 6

Building on FreeBSD 14.4
by Frank Volf 19 May '26

19 May '26

Hi, I'm trying to build dovecot-2.4.4 on FreeBSD 14.4 and I get a strange error message. What I did is download and extract dovecot-2.4.4.tar.gz and then run ./configure without any arguments. After typing make the build started without any problems until this point: .... Making all in auth CC test_auth_cache-auth-cache.o CC test_auth_cache-test-auth-cache.o CC auth-main.o CC auth-auth.o CC auth-auth-cache.o CC auth-auth-client-connection.o CC auth-auth-master-connection.o CC auth-auth-policy.o CC auth-auth-penalty.o CC auth-auth-request.o CC auth-auth-request-fields.o CC auth-auth-request-handler.o CC auth-auth-request-var-expand.o CC auth-auth-sasl-mech-apop.o CC auth-auth-sasl-mech-dovecot-token.o CC auth-auth-sasl-mech-oauth2.o CC auth-auth-sasl.o CC auth-auth-settings.o CC auth-auth-fields.o CC auth-auth-token.o CC auth-auth-worker-connection.o CC auth-auth-worker-server.o CC auth-db-oauth2.o CC auth-db-sql.o CC auth-db-passwd-file.o CC auth-passdb.o CC auth-passdb-blocking.o CC auth-passdb-bsdauth.o CC auth-passdb-cache.o CC auth-passdb-oauth2.o CC auth-passdb-passwd.o CC auth-passdb-passwd-file.o CC auth-passdb-pam.o CC auth-passdb-sql.o CC auth-passdb-static.o CC auth-userdb.o CC auth-userdb-blocking.o CC auth-userdb-passwd.o CC auth-userdb-passwd-file.o CC auth-userdb-prefetch.o CC auth-userdb-static.o CC auth-userdb-sql.o CC auth-db-ldap.o CC auth-db-ldap-sasl.o CC auth-db-ldap-settings.o CC auth-passdb-ldap.o CC auth-userdb-ldap.o CC auth-db-lua.o CC auth-passdb-lua.o CC auth-userdb-lua.o make[3]: don't know how to make -L/usr/local/lib. Stop make[3]: stopped making "all" in /home/volf/dovecot-2.4.4/src/auth *** Error code 1 So, apparently make is confused and thinks that the compiler/linker commandline option is an item to build. I'm at loss how to solve this. I would appreciate it, if somebody could give me a hint how to solve this. Kind regards, Frank Hi, I'm trying to build dovecot-2.4.4 on FreeBSD 14.4 and I get a strange error message. What I did is download and extract dovecot-2.4.4.tar.gz and then run ./configure without any arguments. After typing make the build started without any problems until this point: .... Making all in auth CC test_auth_cache-auth-cache.o CC test_auth_cache-test-auth-cache.o CC auth-main.o CC auth-auth.o CC auth-auth-cache.o CC auth-auth-client-connection.o CC auth-auth-master-connection.o CC auth-auth-policy.o CC auth-auth-penalty.o CC auth-auth-request.o CC auth-auth-request-fields.o CC auth-auth-request-handler.o CC auth-auth-request-var-expand.o CC auth-auth-sasl-mech-apop.o CC auth-auth-sasl-mech-dovecot-token.o CC auth-auth-sasl-mech-oauth2.o CC auth-auth-sasl.o CC auth-auth-settings.o CC auth-auth-fields.o CC auth-auth-token.o CC auth-auth-worker-connection.o CC auth-auth-worker-server.o CC auth-db-oauth2.o CC auth-db-sql.o CC auth-db-passwd-file.o CC auth-passdb.o CC auth-passdb-blocking.o CC auth-passdb-bsdauth.o CC auth-passdb-cache.o CC auth-passdb-oauth2.o CC auth-passdb-passwd.o CC auth-passdb-passwd-file.o CC auth-passdb-pam.o CC auth-passdb-sql.o CC auth-passdb-static.o CC auth-userdb.o CC auth-userdb-blocking.o CC auth-userdb-passwd.o CC auth-userdb-passwd-file.o CC auth-userdb-prefetch.o CC auth-userdb-static.o CC auth-userdb-sql.o CC auth-db-ldap.o CC auth-db-ldap-sasl.o CC auth-db-ldap-settings.o CC auth-passdb-ldap.o CC auth-userdb-ldap.o CC auth-db-lua.o CC auth-passdb-lua.o CC auth-userdb-lua.o make[3]: don't know how to make -L/usr/local/lib. Stop make[3]: stopped making "all" in /home/volf/dovecot-2.4.4/src/auth *** Error code 1 So, apparently make is confused and thinks that the compiler/linker commandline option is an item to build. I'm at loss how to solve this. I would appreciate it, if somebody could give me a hint how to solve this. Kind regards, Frank

6 13

flatcurve index size (10x larger than lucene)
by Jean-Daniel Beaubien 19 May '26

19 May '26

Hi everyone, I am currently trying to update from an old dovecot 2.3 setup with fts-lucene to 2.4.2 with fts-flatcurve. However, I am seeing a giant jump in the size of the indexes. For an email account that takes 12GB of storage, I get the following index sizes: - lucene: 270 MB - flatcurve: 2400 MB That is almost a 10x increase in the index size (with flatcurve the indexes represent 20% of the size of the mailbox). Considering I have a mailbox that takes 270GB, I can't imagine the size of the indexes. *Am I doing something wrong with flatcurve? How can the indexes be so much larger than lucene?* I took the default flatcurve configuration from the Ubuntu 26.04 install: mail_plugins { fts = yes fts_flatcurve = yes } fts_autoindex = yes language_filters = normalizer-icu snowball stopwords language_tokenizers = generic email-address language_tokenizer_generic_algorithm = simple language en { default = yes filters = lowercase snowball english-possessive stopwords } fts flatcurve { # All of these are optional, and indicate the default values. # They are listed here for documentation purposes; most people should not # need to define/override in their config. # commit_limit = 500 # max_term_size = 30 # min_term_size = 2 # optimize_limit = 10 # rotate_count = 5000 # rotate_time = 5000 substring_search = yes } *Any help/insight would be greatly appreciated.* Best regards, -J Hi everyone, I am currently trying to update from an old dovecot 2.3 setup with fts-lucene to 2.4.2 with fts-flatcurve. However, I am seeing a giant jump in the size of the indexes. For an email account that takes 12GB of storage, I get the following index sizes: o lucene: 270 MB o flatcurve: 2400 MB That is almost a 10x increase in the index size (with flatcurve the indexes represent 20% of the size of the mailbox). Considering I have a mailbox that takes 270GB, I can't imagine the size of the indexes. Am I doing something wrong with flatcurve? How can the indexes be so much larger than lucene? I took the default flatcurve configuration from the Ubuntu 26.04 install: mail_plugins { fts = yes fts_flatcurve = yes } fts_autoindex = yes language_filters = normalizer-icu snowball stopwords language_tokenizers = generic email-address language_tokenizer_generic_algorithm = simple language en { default = yes filters = lowercase snowball english-possessive stopwords } fts flatcurve { # All of these are optional, and indicate the default values. # They are listed here for documentation purposes; most people should not # need to define/override in their config. # commit_limit = 500 # max_term_size = 30 # min_term_size = 2 # optimize_limit = 10 # rotate_count = 5000 # rotate_time = 5000 substring_search = yes } Any help/insight would be greatly appreciated. Best regards, -J

3 3

[Dovecot] batch convert mbox to maildir
by Netlink Tech 18 May '26

18 May '26

Hello, I have used mb2md for an individual user like this: su ~username cd ~ ./mb2md -m This converted /var/spool/mail/username mbox to /home/users/username/Maildir just as I expected. To convert 100s of users the same way would be a chore (su as each user for permissions, etc.). Is there a way to batch process all /var/spool/mail/$USER to /home/users/$USER/Maildir with the correct permissions/file owners for each user?

4 4

Lua authentication
by John Fawcett 18 May '26

18 May '26

Hi I'm finally getting round to taking up Aki's suggestion here to look into lua. The original requirement was to check the ip reputation giving an OK or KO before proceeding to the login. I'd be interested in any feedback on the dovecot.conf settings and lua script. Also I've encountered a strange caching issue. https://dovecot.org/mailman3/archives/list/dovecot@dovecot.org/thread/E5FLX… To do this I've added a new passdb before the existing sql passdb. I am assuming that I will need to reverse the defaults (in 2.3.21.1) for result_success and result_failure. passdb { driver = lua args = file=/etc/dovecot/passdb.lua blocking=yes result_success = continue result_failure = return-fail } This is my lua test script. function auth_passdb_lookup(req) dovecot.i_info("login request from " .. req.remote_ip .. " user=" .. req.user) if (req.user == "user_to_deny(a)example.com") then dovecot.i_info("deny login") return dovecot.auth.PASSDB_RESULT_USER_UNKNOWN, "" end return dovecot.auth.PASSDB_RESULT_NEXT, "" end I am trying to get this working with this very simple logic before developing the real logic. But basically I am considering two responses from the lua script, one which is OK (returning dovecot.auth.PASSDB_RESULT_NEXT) in which case the next passdb should be consulted for the real password lookup. The other case is a KO (returning dovecot.auth.PASSDB_RESULT_USER_UNKNOWN) where this should be taken as an immediate failure without proceeding to password lookup in the next passd.I have passdb caching disabled. While testing the KO case which seems to be working, if I modify the script changing the user_to_deny(a)example.com so it no longer matches, the script still outputs "deny login". It's not a passdb caching issue since it is going through the "deny login" code despite the user not matching. Could it be that lua scripts are being cached by dovecot? John

1 0

Re: [EXT] Re: postfix/dovecot migration
by bcs＠nanomail.net 16 May '26

16 May '26

Was able to execute the process as root with "doveadm -D backup -Ru tst tcp:10.0.1.212:12354" after updating some destination side configuration options that do not appear to be documented in the link provided, but there are a few errors that I am unable to understand or correct. 1. Debug: open(/proc/self/io) failed: Permission denied - This file is read only for root and permissions cannot be modified. 2. Error: Mailbox INBOX sync: mailbox_delete failed: INBOX can't be deleted. - Not sure why a mailbox would need to be deleted other than the backup is using a delete and recreate to retain only current emails, assuming this is on the destination server. 3. All emails for tst account are deleted from the source server - This is a significant issue when only copies should be made for a backup. Full log is attached. Any additional insights would be greatly appreciated, Bryan May 15, 2026 10:01 AM, "Aki Tuomi" <aki.tuomi(a)open-xchange.com> wrote: > Yeah, you can do migration with dsync or imap between 2.3 and 2.4 > > Aki > >> On 15/05/2026 16:10 EEST Bryan Simmons <bcs(a)nanomail.net> wrote: >> >> Aki, >> >> Thank you for the guidance. Just to confirm, doveadm/imap based >> migration is the section under "Migrating Mailboxes from Another Dovecot >> Server" in the link referenced below since this migration will be >> between servers? >> >> Seems an upgrade from dovecot 2.3.21 (current version on source server) >> to 2.4.2 (installed version on the destination server) would be >> appropriate before migrating any user accounts based on information from >> some of the other posts regarding migration. >> >> Thanks , Bryan >> >> On 5/13/26 13:41, Aki Tuomi via dovecot wrote: >> On 13/05/2026 20:31 EEST Bryan Simmons via dovecot <dovecot(a)dovecot.org> wrote: >> >> Moving postfix and dovecot to a new server including all current users >> and emails. There exists several dovecot files in each user mail directory: >> >> dovecot.index >> dovecot.index.cache >> dovecot.index.log >> dovecot-keywords >> dovecot.list.index.log >> dovecot.mailbox.log >> dovecot-uidlist >> dovecot-uidvalidity >> dovecot-uidvalidity.612d3d34 >> >> Should these files be migrated also or will dovecot recreate them as needed? >> >> Thank you, Bryan >> >> https://doc.dovecot.org/2.4.4/core/admin/migration.html#migrating-mailboxes >> >> I would recommend seeing this. Depending on your mailbox format, it can be important that those >> files are copied, but I would suggest doveadm/imap based migration. >> >> Aki >> >> _______________________________________________ >> dovecot mailing list -- dovecot(a)dovecot.org >> To unsubscribe send an email to dovecot-leave(a)dovecot.org

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Panic: file charset-iconv.c: line 83 (charset_to_utf8_try): assertion failed: (srcleft <= CHARSET_MAX_PENDING_BUF_SIZE)
by Alex Rosenberg 15 May '26

15 May '26

Attached is an LLM-reduced reproduction of the crash in the title. My particular setup is dovecot 2.3.21.1 (d492236fa0) in a FreeBSD jail (13.5). I realize that this is an older release but there is no FreeBSD port/pkg for dovecot 2.4.x yet. The message in the attachment is reduced from an old (2017!) email to one of the LLVM compiler mailing lists. The original malformed email had this header: X-Mailer: Evolution 3.22.5 (3.22.5-1.fc25) The bug occurs when dovecot's FTS indexer processes a MIME part that: 1. Declares charset="UTF-7" 2. Contains base64-encoded content that, when decoded, has bare '+' characters 3. Causes UTF-7 decoder buffer overflow in charset-iconv.c:83 The base64 content decodes to C source code with expressions like: - argc + 4 - state++ - state-- These '+' characters in UTF-7 context cause the decoder's pending buffer to exceed CHARSET_MAX_PENDING_BUF_SIZE, triggering the assertion failure. Alex

4 5

Can't find unicode/ustring.h in test
by mr.thesaw＠gmail.com 14 May '26

14 May '26

I get this error during compilation: make[3]: Entering directory '/home/hacksaw/src/dovecot-2.4.4/src/lib-language' CC test-lang-icu.o In file included from test-lang-icu.c:8: lang-icu.h:4:10: fatal error: unicode/ustring.h: No such file or directory 4 | #include <unicode/ustring.h> | ^~~~~~~~~~~~~~~~~~~ compilation terminated. I have unicode 66, at least as far as Ubuntu is concerned.

2 8

Dovecot 2.4.4 - mail_crypt with per-user Global Keys from LDAP (not Folder Keys)
by luis.neapolis＠gmail.com 14 May '26

14 May '26

Hi everyone, I'm trying to configure Dovecot 2.4.4 with per-user encryption keys stored in LDAP, using Global Keys mode (NOT Folder Keys). My goal: Each user has their own public key and private key (encrypted with the user's login password) stored in LDAP attributes. 1) LMTP should use the public key to encrypt incoming emails. 2) IMAP should use the user's login password to decrypt the private key from LDAP, then decrypt the emails. I want to use Global Keys mode (where keys are provided via userdb), NOT Folder Keys (where Dovecot stores keys in dovecot-attributes files). What works: LMTP receives emails and encrypts them correctly using the user's public key from LDAP and the encrypted files are saved to disk. What doesn't work: IMAP can log in and see the email list (subject, from, date), but the email body never loads. Error: Decryption error: no private key available May 14 18:58:45 host dovecot[295725]: imap(test(a)example.com)<295760><SESSIONID>: Debug: Mailbox INBOX: UID 11: Opened mail because: prefetch May 14 18:58:45 host dovecot[295725]: imap(test(a)example.com)<295760><SESSIONID>: Debug: dict(file): Looking up 'priv/a82ea60599ba056ad47904003a5aeee9/vendor/vendor.dovecot/pvt/crypt/privkeys/aacbcb614fb59f81e9519186b12ac8862858d89fa3bcc1be5f25b886d3e95ee3' May 14 18:58:45 host dovecot[295725]: imap(test(a)example.com)<295760><SESSIONID>: Debug: dict(file): Lookup finished for 'priv/a82ea60599ba056ad47904003a5aeee9/vendor/vendor.dovecot/pvt/crypt/privkeys/aacbcb614fb59f81e9519186b12ac8862858d89fa3bcc1be5f25b886d3e95ee3': not found May 14 18:58:45 host dovecot[295725]: imap(test(a)example.com)<295760><SESSIONID>: Error: Mailbox INBOX: UID 11: read() failed: read(/mail/example.com/test/cur/1778773528.M279604P294174.host.example.com,… failed: Decryption error: no private key available (FETCH BODY[1]) The confusing part: IMAP has the user's password (the user authenticated successfully). The private key in LDAP is encrypted with that same password. So IMAP should be able to decrypt the private key, then decrypt the email. But Dovecot is not using the password it already has to unlock the private key. My configuration: dovecot_config_version = 2.4.4 mail_plugins { quota = yes } # Empty global key block (workaround for LMTP not to fail) crypt_global_private_key main { } passdb ldap { driver = ldap filter = (&(objectClass=Account) (mail=%{user})) fields { mail = %{ldap:mail} password = %{ldap:userPassword} userdb_home = %{ldap:homeDirectory} } } userdb ldap { driver = ldap filter = (&(objectClass=Account) (mail=%{user})) fields { home = %{ldap:homeDirectory} uid = %{ldap:uidNumber|default('500')} gid = %{ldap:gidNumber|default('500')} # Per-user keys from LDAP (Global Keys mode) crypt_global_public_key_file = inline:%{ldap:userPublicKey} crypt_global_private_key/main/crypt_private_key_file = inline:%{ldap:userPrivateKey} crypt_private_key_password = %{password} } } protocol imap { mail_plugins { imap_quota = yes mail_crypt = yes } protocol lmtp { mail_plugins { sieve = yes mail_crypt = yes } } Note: I do NOT have mail_attribute_dict configured. I do NOT want Dovecot to store keys in local files. I want everything to come from LDAP. What I've verified: 1) The private key is valid and decrypts correctly with the user's password using openssl pkey -passin pass:xxx. 2) doveadm user shows the keys are retrieved from LDAP. The error persists. The question: Since IMAP already has the user's password (from the successful login), how can I make Dovecot use that password to decrypt the private key from LDAP and then decrypt the emails? Is there a specific setting I'm missing? Does crypt_private_key_password = %{password} need to be placed somewhere else (e.g., inside the protocol imap block) to work correctly? Also, I see in the logs that Dovecot is still looking for dict(file) keys (Folder Keys mode). How can I completely disable Folder Keys behavior and force Dovecot to only use Global Keys from LDAP? Thank you! Dovecot version: 2.4.4-5 OS: AlmaLinux 9.7 Mail storage: Maildir

1 0

Backup problem
by Doug Hardie 13 May '26

13 May '26

I just migrated my mail server to a new machine. When the new machine was back up and running, I found one mailbox that used to have many emails, now only had 3. I went back to the old machine and found there were only those three messages in the mailbox. I suspect somehow I managed to delete them prior to the backup to the new machine. I have a copy of that mailbox on a backup machine. I just checked and all are there. They have file names like: 1658299911.M966551P8821.mail,S=5001,W=5108:2,S 1664572476.M701757P94428.mail,S=4051,W=4135:2,Sab 1665119988.M609674P37848.mail,S=8455,W=8629:2,Sab 1665757235.M137163P32739.mail,S=5838,W=5950:2,S 1665774793.M299412P37846.mail,S=4669,W=4755:2,S 1665782571.M706364P40033.mail,S=12191,W=12379:2,S The backup machine has all the dovecot files for that user. How can I restore those email from the backup machine to the new server? -- Doug

2 1

Can I use a static userdb or no?
by social+17dw1scw＠lombra.net 13 May '26

13 May '26

Hi, I've been researching this for a while now, and can't find a definitive answer. I have a virtual setup, with globally static UID, GID and mail locations set. The documentation is clear that this lets me use a static userdb instead of SQL. But then, doveadm mailbox list -A requires that a valid iterate_query is set, and that requires an SQL userdb. So, which is it? If querying does not work with a static userdb, that seems like a significant caveat. I'm also curious how this works with prefetch. I understand I can make the passdb query return static values, but I figure since I already have those configured, I shouldn't need to do that. How can I determine whether prefetching is working as intended? Thank you.

3 2

postfix/dovecot migration
by Bryan Simmons 13 May '26

13 May '26

Moving postfix and dovecot to a new server including all current users and emails. There exists several dovecot files in each user mail directory: dovecot.index dovecot.index.cache dovecot.index.log dovecot-keywords dovecot.list.index.log dovecot.mailbox.log dovecot-uidlist dovecot-uidvalidity dovecot-uidvalidity.612d3d34 Should these files be migrated also or will dovecot recreate them as needed? Thank you, Bryan

2 1

Expand dovecot recipients from ldap group
by Maksim Rodin 13 May '26

13 May '26

Hello, I have set up dovecot (2.3.21) to get its recipients from Active Directory. I can successfully get recipients from Active Directory user objects using their sAMAccountName: # cat /etc/dovecot/local.conf ... passdb users { driver = ldap args = /etc/dovecot/dovecot-ldap_domain.conf.ext } userdb users { driver = static args = uid=vmail gid=vmail } ... Here is the relevant part of the ldap config: # cat /etc/dovecot/dovecot-ldap_domain.conf.ext ... user_attrs = \ =home=/vmail/%{ldap:sAMAccountName}, \ =uid=vmail, \ =gid=vmail pass_filter = (&(objectCategory=person)(mail=%u)) user_filter = (&(objectCategory=person)(mail=%u)) ... I can also successfully get user aliases from Active Directory user objects using their otherMailbox attribute: # cat /etc/dovecot/local.conf ... userdb aliases { driver = ldap args = /etc/dovecot/dovecot-ldap_domain_aliases.conf.ext } ... Here is the relevant part of the ldap config: # cat /etc/dovecot/dovecot-ldap_domain_aliases.conf.ext: ... user_attrs = \ =home=/vmail/%{ldap:sAMAccountName}, \ =uid=vmail, \ =gid=vmail pass_filter = (&(objectCategory=person)(otherMailbox=%u)) user_filter = (&(objectCategory=person)(otherMailbox=%u)) Now I am struggling with the task of getting recipients from Active Directory group objects to handle them as distribution groups. Is there a way to expand an Active Directory group object to multiple recipients? I know all of this can be done with postfix ldap module, but I would like to handle all the delivery tasks to dovecot LMTP. -- Best regards Maksim Roin

1 0

Sync'ing two dovecot servers
by Marc Singer 12 May '26

12 May '26

Greetings, I was pleased to see that dovecot has a sync function in doveadm. So far, other tools for moving mailbox contents from one server to another has not been successful. However. Perhaps I don't understand how this should work. I have a new containerized dovecot v2.4.2 # 2.4.2 (0962ed2104): /etc/dovecot/dovecot.conf # OS: Linux 6.12.63+deb13-amd64 x86_64 and I have an existing dovecot running in a VPS: # 2.3.19.1 (9b53102964): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.19 (4eae2f79) # OS: Linux 6.1.0-35-amd64 x86_64 Debian 12.11 I want to move one user, as a test. I execute this in the container. # doveadm sync -R1 -u USER tcps:OLD_SERVER:993 doveadm(USER): Error: conn OLD_SERVER:993 (IP:993): doveadm server sent invalid handshake: * OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE LITERAL+ AUTH=PLAIN AUTH=LOGIN] Dovecot (Debian) ready. doveadm(USER): Error: cmd sync: Disconnected from remote: Connection closed I'm pretty sure that doveadm sync was able to negotiate the TLS connection. I don't see what it could object to in the sign-on. What am I missing? Cheers -- /Marc Oscar Singer/ *Woollysoft* Dial 817.1823.602.1+ from right to left. Greetings, I was pleased to see that dovecot has a sync function in doveadm. So far, other tools for moving mailbox contents from one server to another has not been successful. However. Perhaps I don't understand how this should work. I have a new containerized dovecot v2.4.2 # 2.4.2 (0962ed2104): /etc/dovecot/dovecot.conf # OS: Linux 6.12.63+deb13-amd64 x86_64 and I have an existing dovecot running in a VPS: # 2.3.19.1 (9b53102964): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.19 (4eae2f79) # OS: Linux 6.1.0-35-amd64 x86_64 Debian 12.11 I want to move one user, as a test. I execute this in the container. # doveadm sync -R1 -u USER tcps:OLD_SERVER:993 doveadm(USER): Error: conn OLD_SERVER:993 (IP:993): doveadm server sent invalid handshake: * OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE LITERAL+ AUTH=PLAIN AUTH=LOGIN] Dovecot (Debian) ready. doveadm(USER): Error: cmd sync: Disconnected from remote: Connection closed I'm pretty sure that doveadm sync was able to negotiate the TLS connection. I don't see what it could object to in the sign-on. What am I missing? Cheers -- Marc Oscar Singer Woollysoft Dial 817.1823.602.1+ from right to left.

5 7

Dovecot and Pigeonhole v2.4.4 Released
by Aki Tuomi 12 May '26

12 May '26

Hi! We are happy to publish version 2.4.4 of Dovecot and Pigeonhole. These contain CVEs, discovered by external researches. The majority of these have been discovered with help of automated code analysis tools like claude code security, which is why some of these are rather old, missed bugs. No new supported distros have been added or old removed, no new dependencies have been added. Note that there are experimental features in 2.4, one is enabled with `--enable-experimental-mail-utf8`, and another with `--enable-experimental-imap4rev2`, and you also need to set mail_utf8_extensions=yes and imap4rev2_enabled=yes to enable them in config. https://dovecot.org/releases/2.4/dovecot-2.4.4.tar.gz https://dovecot.org/releases/2.4/dovecot-2.4.4.tar.gz.sig https://pigeonhole.dovecot.org/releases/2.4/dovecot-pigeonhole-2.4.4.tar.gz https://pigeonhole.dovecot.org/releases/2.4/dovecot-pigeonhole-2.4.4.tar.gz… Binary packages in https://repo.dovecot.org/ Docker images in https://hub.docker.com/r/dovecot/dovecot --- * CVE-2026-27851: lib-var-expand: Safe filter marks all following pipelines safe. * CVE-2026-33603: auth: CRAM-SHA-*-PLUS channel binding could be faked. MITM attacker with a certificate trusted by the client could have bypassed the requirement for channel binding. * CVE-2026-40020: IMAP folders can be shared-spammed to everyone. * CVE-2026-42006: An attacker can cause uncontrolled memory usage with excessive bracing over IMAP. The fix in CVE-2026-27857 was incomplete. * indexer-worker, quota-status, script-login, program-client-local: Root privileges are now dropped permanently before serving requests. * indexer-worker: Default restart_request_count changed to 1 to work correctly after permanent root privilege drop. * lmtp: Add back service_extra_groups=$SET:default_internal_group that was incorrectly removed in v2.4.3. * master: inet_listener_reuse_port has been replaced by service_reuse_port. The new setting properly pre-creates all listener sockets at startup and assigns one unique socket per process. Using this allows evenly distributing incoming connections to login processes. See https://doc.dovecot.org/latest/core/config/service.html#service_reuse_port for details. - auth: Fix LDAP escaping of 0x13 control character. - auth: Use timing-safe comparison for certificate and public key fingerprints. - fts: Correctly handle internal http-client response errors. - fts: Don't send request to Tika if there is no body text. - fts: Fix address header indexing for RFC 2047 encoded-words. - fts: tika, fts-solr: Fix use-after-free crash during DNS lookup. - imap: Fix assertion panic on invalid REPLACE 0 command. - lib-auth-client: Avoid "unknown id" errors for aborted auth requests. - lib-dcrypt: Fix potential crash if trying to access untrusted/corrupted keys. - lib-dcrypt: Improve error message if keys aren't in hex format as expected. - lib-index: Fix potential crash if fsck fails. - lib-ldap: Fix using OpenLDAP default CA when ssl_client_ca_dir/file is unset. v2.4.3 regression. - lib-master, master: Fix behavior for services with client_limit>1 and restart_request_count so that processes reaching restart_request_count are no longer counted towards process_limit. - lib-master: Fix crash when reaching client_limit with restart_request_count>1. - lib-master: haproxy - Don't trust client certificate common name when HAProxy reports verification failure. - lib-sasl: cram-md5 - Fix out of bounds memory read. - lib-sasl: oauth2 - Fix one byte out of bounds read. - lib-sql: cassandra - Fix reusing Cassandra SSL connections. - lib-sql: sqlite - Fix sqlite_journal_mode=wal to actually work. - lib-storage: Auto-rename non-NFC subscription file entries to NFC on read. - lib-storage: Prevent non-atom SEARCH keywords from causing IMAP command injection. - lib-var-expand-crypt: Return error if hex decoding fails. - lib-var-expand: Fix crash (SIGFPE) with non-positive divisor for / and %. - log: Fix memory leak at deinit. - login-common: When process is full, don't destroy clients waiting on master auth. - login-proxy: Fix crash with rawlog and multiplexing during reconnection. - mail-compress: Fix panic when save method unavailable. - mail-crypt: Fix crash when HMAC-based algorithm is used. - mail-crypt: Use AEAD instead of HMAC with ChaCha20-Poly1305. - mdbox: Create files with O_NOFOLLOW. - push-notification: ox - Fix use-after-free crash during DNS lookup. - quota: quota-status - Limit input buffer size to 1 kB. ––- * CVE-2026-40016: sieve :contains and :matches operators could have been using excessive amount of CPU. Limit the CPU to sieve_max_cpu_time. - Fix potential crashes parsing corrupted Sieve binaries. - lib-sieve: matches - Fix trailing literal match when it fills value exactly. v2.4.3 regression.

2 2

Dovecot Security Advisory OXDC-2026-0002
by Aki Tuomi 12 May '26

12 May '26

Hi! We're sharing our latest advisory with you and like to thank everyone who contributed in finding and solving those vulnerabilities. This advisory is also published at https://documentation.open-xchange.com/dovecot/security/advisories/html/202… --- Classification: TLP:GREEN Internal reference: DOV-8967 Type: CWE-235 (Improper Handling of Extra Parameters) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Last affected revision: OX Dovecot Pro core 3.1.4, OX Dovecot CE core 2.4.3 First fixed revision: OX Dovecot Pro core 3.1.5, OX Dovecot CE core 2.4.4 Discovery date: 2026-03-29 Solution date: 2026-05-05 Disclosure date: 2026-05-05 Researcher credits: caprinuxx@yeswehack CVE: CVE-2026-27851 CVSS: 7.4 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N) Details: lib-var-expand: Safe filter leaks to all following pipelines. When safe filter is used with variable expansion, all following pipelines on the same string are incorrectly interpreted as safe too, enabling unsafe data to be unescaped. Risk: This can enable SQL / LDAP injection attacks when used in authentication. No publicly available exploits are known. Solution: Avoid using safe filter until on fixed version. --- Internal reference: DOV-8948 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Last affected revision: OX Dovecot Pro core 2.3.0 First fixed revision: OX Dovecot Pro core 3.1.5, OX Dovecot CE core 2.4.4 Discovery date: 2026-03-24 Solution date: 2026-05-05 Disclosure date: 2026-05-05 Researcher credits: djvirus@yeswehack CVE: CVE-2026-40016 CVSS: 5.3 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H) Details: Sieve :contains/:matches O(N×M) Substring Match Bypasses sieve_max_cpu_time Limit (130× Overrun). Attacker can upload a malicious Sieve script over ManageSieve service (or locally) to bypass configured CPU time limits for Sieve up to 130 times of the configured limit. Risk: Attacker can use this to degrade server performance and bypass configured CPU time limits for Sieve scripts. No publicly available exploits are known. Solution: Install fixed version, or alternatively prevent direct access to Sieve scripts via ManageSieve or local access. --- Internal reference: DOV-9030 Type: CWE-99 (Improper Control of Resource Identifiers ('Resource Injection')) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Last affected revision: OX Dovecot Pro core 3.1.0, OX Dovecot CE core 2.4.0 First fixed revision: OX Dovecot Pro core 3.1.5, OX Dovecot CE core 2.4.4 Discovery date: 2026-04-08 Solution date: 2026-05-05 Disclosure date: 2026-05-05 Researcher credits: ylwango613@yeswehack CVE: CVE-2026-33603 CVSS: 6.8 (CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N) Details: login: Base64 input can contain tabs that bypass IPC protection. Attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding. This requires that the attacker is able to position itself between Dovecot and the client connection. Risk: If successful, the attacker can eavesdrop communications between Dovecot and client as MITM proxy. No publicly available exploits are known. Solution: Install fixed version. --- Internal reference: DOV-9040 Type: CWE-284 (Improper Access Control) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Last affected revision: OX Dovecot Pro core 2.3.0 First fixed revision: OX Dovecot Pro core 3.1.5, OX Dovecot CE core 2.4.4 Discovery date: 2026-04-08 Solution date: 2026-05-05 Disclosure date: 2026-05-05 Researcher credits: ilhamaf@yeswehack CVE: CVE-2026-40020 CVSS: 3.1 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L) Details: IMAP folders can be shared-spammed to everyone. Attacker can use the IMAP SETACL command to inject the anyone permission to user's dovecot-acl file even if imap_acl_allow_anyone=no. This causes folders to be spammed to all users. Risk: The impact is limited to being able to spam folders to other users, no unexpected access is gained. No publicly available exploits are known. Solution: Install to fixed version. --- Internal reference: DOV-9138 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Last affected revision: OX Dovecot Pro core 3.0.5, OX Dovecot Pro core 3.1.4, OX Dovecot CE core 2.4.3 First fixed revision: OX Dovecot Pro core 3.1.5, OX Dovecot CE core 2.4.4 Discovery date: 2026-04-27 Solution date: 2026-05-05 Disclosure date: 2026-05-05 Researcher credits: D4RKCYPH3R@yeswehack CVE: CVE-2026-42006 CVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L) Details: imap-login: Excessive memory usage DoS - Try 2. An attacker can cause uncontrolled memory usage with excessive bracing over IMAP. The fix in CVE-2026-27857 was incomplete, only blocking one way of doing this, so there was still another way left open. In particular, the fix was for closing braces, but you could still use open braces to bypass the limit. Risk: Using excessive bracing, attacker can cause memory usage up to configured memory limit. No publicly available exploits are known. Solution: Install fixed version, or configure vsz_limit for imap process to low value.

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Changed location of index files
by Lafiel Elentari 11 May '26

11 May '26

Hello. After upgrading to version 2.4, index files were moved to the user's home directory, and the `mail_path = ~/mail` parameter was no longer taken into account when processing index files. In addition, indexes for the `INBOX` folder no longer respect the `mail_index_path=` parameter and are stored in the `./INBOX/dovecot.index.*` folder, although they should be stored in the same folder where the messages are stored, given the current configuration. My configuration: ``` mail_home = mail_inbox_path = mail_index_path = mail_path = ~/mail userdb declarative { passwd_file_path = /var/data/mail/dovecot/passdb driver = passwd-file fields { home = /var/data/mail/vmail/%{user | domain}/%{user | username} mail_index_path = /var/data/mail/vmail/%{user | domain }/%{user | username} } } ``` Current location of index files: ``` /var/data/mail/vmail/example.com/user ├── INBOX │ ├── dovecot.index.cache │ └── dovecot.index.log ├── Sent │ ├── dovecot.index.cache │ └── dovecot.index.log ├── Drafts │ └── dovecot.index.log ├── Junk │ └── dovecot.index.log ├── Trash │ ├── dovecot.index.cache │ └── dovecot.index.log ├── dovecot.list.index ├── dovecot.list.index.log └─── mail ├── cur ├── new ├── tmp ├── Sent │ ├── cur │ ├── new │ ├── tmp │ └── dovecot-uidlist ├── Drafts │ ├── cur │ ├── new │ ├── tmp │ └── dovecot-uidlist ├── Junk │ ├── cur │ ├── new │ ├── tmp │ └── dovecot-uidlist ├── Trash │ ├── cur │ ├── new │ ├── tmp │ └── dovecot-uidlist ├── subscriptions ├── dovecot.mailbox.log ├── dovecot-uidlist ├── dovecot-uidvalidity └── dovecot-uidvalidity.69d94118 ``` Expected location of index files according to configuration: ``` /var/data/mail/vmail/example.com/user └─── mail ├── cur ├── new ├── tmp ├── Sent │ ├── cur │ ├── new │ ├── tmp │ ├── dovecot.index │ ├── dovecot.index.cache │ ├── dovecot.index.log │ └── dovecot-uidlist ├── Drafts │ ├── new │ ├── tmp │ ├── cur │ ├── dovecot.index │ ├── dovecot.index.cache │ ├── dovecot.index.log │ └── dovecot-uidlist ├── Junk │ ├── new │ ├── tmp │ ├── cur │ ├── dovecot.index │ ├── dovecot.index.cache │ ├── dovecot.index.log │ └── dovecot-uidlist ├── Trash │ ├── cur │ ├── new │ ├── tmp │ ├── dovecot.index │ ├── dovecot.index.cache │ ├── dovecot.index.log │ └── dovecot-uidlist ├── dovecot.index ├── dovecot.index.cache ├── dovecot.index.log ├── dovecot.list.index ├── dovecot.list.index.log ├── dovecot.mailbox.log ├── dovecot-uidlist ├── dovecot-uidvalidity ├── dovecot-uidvalidity.69d94118 └── subscriptions ``` -- Best regards, Lafiel Elentari mailto:lafiel@elven.pw

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Dovecot 2.3.21.1 missing dbox-Mails folder causes IMAP folder which can not be deleted? Possible known bug?
by Benoit Panizzon 11 May '26

11 May '26

Hi Team Running Dovecot 2.3.21.1 in an ISP environment using dbox format as storage and built in dovecot replication to a secondary storage. => I know, it's not new - migration to 2.4 with completely replacing replication is pending. For quite some time we are fighting issues with customers which are unable to delete IMAP folder. Those folder end up in status \NoSelect When you issue a 'delete' for the folder, it is successful, but either the folder is back after logout/login or back right away when you list the folders. Usual remedy: completely delete mail index of affected mailbox on both, primary and secondary storage, delete complete mail storage on secondary, resync with doveadm force-resync, cross filters. Now I had a mailbox where even this did not solve the issue - but I noticed something weird. . delete "mailbox" => OK . delete "mailbox" => OK . create "mailbox" => OK . create "mailbox" => Mailbox does already exist . delete "mailbox" => OK . delete "mailbox" => Mailbox does not exist Now the Mailbox is gone from the file system and is not shown with list anymore. Now I had a closer look at the next affected mailbox on the filesystem. IMAP Foldername: LIST (\Noselect \HasNoChildren) "." INBOX.brokenmbox Filesystem, directories: INBOX/brokenmbox/ => There is no content, no hidden files inside the folder 'broeknmbox' . delete "INBOX.brokenmbox" => OK Checking Filesystem. Nothing changed, still the same. . create "INBOX.brokenmbox" => OK Checking Filesystem: Now we have: INBOX/broeknmbox/dbox-Mails/ all empty. . delete "INBOX.brokenmbox" => OK Checking Filesystem: broeknmbox/dbox-Mails/ are both gone within INBOX! Conclusion: Dovecot seems to get confused, when a directory without dbox-Mails subdirectory exists, fails to delete such directories but still lists them as IMAP folders. Is this a known bug? Is there anything which is know to cause this issue which we could tweak at our configuration? Mit freundlichen Grüssen -Benoît Panizzon- -- I m p r o W a r e A G - Leiter Commerce Kunden ______________________________________________________ Zurlindenstrasse 29 Tel +41 61 826 93 00 CH-4133 Pratteln Fax +41 61 826 93 01 Schweiz Web http://www.imp.ch ______________________________________________________

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Migration Planning for Dovecot 2.3 to 2.4
by Gregory Carter 05 May '26

05 May '26

Hello so I have started planning my 2.3 to 2.4 migration and finished the lab work today for that process. Does anyone know of any tools to migrate the configs from 2.3 to 2.4? Also if you are running 2.4 I would like to hear from you as to how well it is working out. Thanks. Hello so I have started planning my 2.3 to 2.4 migration and finished the lab work today for that process. Does anyone know of any tools to migrate the configs from 2.3 to 2.4? Also if you are running 2.4 I would like to hear from you as to how well it is working out. Thanks.

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Dovecot sieve, help !
by Tommy Berglund 03 May '26

03 May '26

Hi! I need help and advice on how to get sieve working. Postfix dovecot works to receive and send mail but I can't get sieve to work. Domain and user are virtual in mariadb. Tips are welcome. Doveconf -n attached.

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mail_inbox_path in manual
by Daniel Convissor (business) 01 May '26

01 May '26

Hi: Recently upgraded Debian to version 13/Trixie, which brings Dovecot up to 2.4 (with its significant configuration file changes). As mentioned on this list, Debian decided to manually put mail_inbox_path in their distribution's config files (and set it to /var/mail/%{user}).[1] This resulted in mayhem for me because that's not where our mail is. I assume this has happened to others as well. I figured out the problem by looking at mail.log after adding mail_debug=yes to my local Dovecot config file. Perhaps Dovecot's manual can be updated to clarify the situation, please? The Mail Location page[2] warns admins to not touch this setting. The upgrade page[3] does not mention needing to look out for Debian's choice. (Granted, this is a Debian problem, but the Dovecot manual is where people turn to figure out what is happening.) Thank you, --Dan [1] https://dovecot.org/mailman3/archives/list/dovecot@dovecot.org/message/Q6HI… [2] https://doc.dovecot.org/2.4.3/core/config/mail_location.html#mail_inbox_path [3] https://doc.dovecot.org/2.4.3/installation/upgrade/2.3-to-2.4.html -- T H E A N A L Y S I S A N D S O L U T I O N S C O M P A N Y Designing transportation systems everyone can use https://www.AnalysisAndSolutions.com/

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