- dovecot - dovecot.org

Panic: file charset-iconv.c: line 83 (charset_to_utf8_try): assertion failed: (srcleft <= CHARSET_MAX_PENDING_BUF_SIZE)
by Alex Rosenberg 09 May '26

09 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

1 1

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.

8 12

NFC normalization rename errors after 2.3 to 2.4 upgrade (mdbox)
by Jan Münnich 05 May '26

05 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

1 1

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.

3 4

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/

1 0

Confusion about ldap in 2.4
by fc26wuqa＠studserv.uni-leipzig.de 28 Apr '26

28 Apr '26

Hello, With dovecot 2.3 it was clear to me, how I should set up ldap: Include `conf.d/auth-ldap.conf.ext` in `conf.d/10-auth.conf` and include `dovecot-ldap.conf.ext` with the usual parameters like hosts, uris, dn, etc. In dovecot 2.4 I am a little bit confused about whats the best practice. I heard about that .ext files being outdated and examples in the documentation saying I should put everything in dovecot.conf? So If in 2.3 my config would look like this: ``` # auth-ldap.conf.ext passdb { driver = ldap args = /etc/dovecot/dovecot-ldap.conf.ext } userdb { driver = ldap args = /etc/dovecot/dovecot-ldap.conf.ext } ``` ``` # dovecot-ldap.conf.ext hosts = ldap.something.org:636 uris = ldaps://smoething.org dn = cn=something,ou=something,dc=something,dc=org dnspass = somethingsomething auth_bind = yes auth_bind_userdn = uid=%u,ou=something ... ``` I would put something like this in dovecot.conf? Or in auth-ldap.conf.ext? ``` ldap_uris = ldap://ldap.example.org ldap_auth_dn = cn=admin,dc=example,dc=org ldap_auth_dn_password = secret ldap_base = dc=example,dc=org passdb ldap { bind = yes filter = (&(objectClass=posixAccount)(uid=%{user})) fields { user = %{ldap:uid} } } ``` (https://doc.dovecot.org/2.4.3/core/config/auth/databases/ldap.html#dn-lookup)

1 0

Upgrading from 2.4.2 to 2.4.3 broke static password login
by harrison＠hhj.me 28 Apr '26

28 Apr '26

Hey folks, I've got dovecot running via docker on version 2.4.2. Here's what my config extension looks like: ``` # auth_mechanisms = plain login auth_verbose = yes passdb static { password = %{env:USER_PASSWORD} } service lmtp { inet_listener lmtps { port = 31024 ssl = no } } ssl_server_cert_file = /etc/dovecot/ssl/cert.pem ssl_server_key_file = /etc/dovecot/ssl/key.pem ssl = yes auth_allow_cleartext = no namespace inbox { type = private separator = / inbox = yes mailbox Drafts { special_use = \Drafts auto = subscribe } mailbox Junk { special_use = \Junk auto = create } mailbox spam { special_use = \Junk auto = no } mailbox Spam { special_use = \Junk auto = no } mailbox Trash { special_use = \Trash auto = subscribe } mailbox TRASH { special_use = \Trash auto = no } mailbox Sent { special_use = \Sent auto = subscribe } mailbox "Sent Mail" { special_use = \Sent auto = no } mailbox "Sent Messages" { special_use = \Sent auto = no } mailbox Archive { special_use = \Archive auto = create } mailbox "Archives" { special_use = \Archive auto = no } } ``` I have env `USER_PASSWORD` defined in the format of `{PLAIN}REDACTED` This has been humming along fine for a little while. I recently automatically upgraded to 2.4.3 which broke my ability to login via IMAP to retrieve emails (it also broke my local mail transport setup; it was unable to send emails). I could see the following messages in the logs: ``` Apr 27 11:12:09 auth(REDACTED,REDACTED,sasl:plain)<REDACTED>: Info: static: No password returned (and no nopassword) Apr 27 11:12:11 imap-login: Info: Login aborted: Connection closed (auth failed, 1 attempts in 6 secs) (auth_failed): user=<REDACTED>, method=PLAIN, rip=REDACTED, lip=172.17.0.2, TLS, session=<REDACTED> ``` Downgrading back to 2.4.2 "fixed" the problem (I was able to login again; LMTP worked again). I didn't change my config extension between the upgrades. I tried searching https://github.com/search?q=repo%3Adovecot%2Fcore+password&type=issues and I see a few related to passwords but nothing is really jumping out at me. Help? I'm staying pinned on 2.4.2 for now but that's not a long term solution.

2 3

Panic in logs
by Kamil Jońca 26 Apr '26

26 Apr '26

Recently I found in my lda logs: 2025-12-30T07:55:14.717927+01:00 alfa dovecot: lda(kjonca): Error: Raw backtrace: #1 [unw_get_proc_name() failed: -10] -> #2 i_syslog_fatal_handler[0x7f99a2351430] -> #3 i_panic[0x7f99a226d453] -> #4 [unw_get_proc_name() failed: -10] -> #5 [unw_get_proc_name() failed: -10] -> #6 [unw_get_proc_name() failed: -10] -> #7 buffer_append[0x7f99a2345270] -> #8 dregex_code_match_groups[0x7f99a233f1a0] -> #9 [unw_get_proc_name() failed: -10] -> #10 [unw_get_proc_name() failed: -10] -> #11 sieve_match_value[0x7f99a117f770] -> #12 sieve_match[0x7f99a117fa30] -> #13 [unw_get_proc_name() failed: -10] -> #14 sieve_interpreter_continue[0x7f99a117e100] -> #15 sieve_multiscript_run[0x7f99a1190330] -> #16 [unw_get_proc_name() failed: -10] -> #17 mail_deliver[0x7f99a27e54a0] -> #18 main[0x55e371c555e0] -> #19 __libc_start_call_main[0x7f99a1e29f00] -> #20 __libc_start_main_alias_2[0x7f99a1e29fa0] -> #21 _start[0x55e371c566a0] And sadly it seems, that mail is missing (it was passed to pipe program to further processing) KJ -- http://wolnelektury.pl/wesprzyj/teraz/ When you go out to buy, don't show your silver.

4 6

Incorrect ARC signature on emails
by Lafiel Elentari 25 Apr '26

25 Apr '26

Hello. On the mail server, I configured addition of the `Authentication-Results` header with authentication check results. I noticed that emails from the dovecot.org server have an incorrect ARC signature: Authentication-Results: ...; dkim=pass header.d=dovecot.org header.s=... header.b=...; dkim=fail ("body hash did not verify") header.d=... header.s=... header.b=...; arc=reject ("signature check failed: fail, {[1] = sig:dovecot.org:reject}"); spf=pass (...: domain of "dovecot-bounces+...=...(a)dovecot.org" designates ... as permitted sender) smtp.mailfrom="dovecot-bounces+...=...(a)dovecot.org"; dmarc=pass (policy=reject) header.from=dovecot.org ``` -- Best regards, Lafiel Elentari mailto:lafiel@elven.pw

2 2

mbox to maildir migration, same server?
by kjohnson＠eclypse.org 25 Apr '26

25 Apr '26

What is the recommended procedure to migrate from mbox to maildir on a server already running dovecot? Ideally, this procedure would convert messages in an existing mbox INBOX and in ~/mail mboxes (as defined in my dovecot configuration) to storage in a ~/Maildir. Some of the INBOXs are rather large -- 100's of MB (one of the reasons for migrating). What I have tried has not worked for me. Below, I describe what I tried, how I tested before I tried, what went wrong, and the current setup (pre-migration). What I tried: ============= stop exim4 service dovecot stop Make dovecot listen only locally, not to external connections. /etc/dovecot/local.conf protocol imap { listen = 127.0.0.1:143 ssl_listen = 127.0.0.1:993 } protocol pop3 { listen = 127.0.0.1:110 ssl_listen = 127.0.0.1:995 } Modify dovecot configuration for maildir: Watch capitalization! #in 10-mail.conf: mail_location = maildir:/home/%u/Maildir namespace inbox { separator = / } dovecot -n, to confirm results and perform limited syntax checking. service dovecot start for each user, in a bash script: dsync -v -u "$U" mirror "mbox:/home/$U/mail:INBOX=/var/mail/$U" (if the conversion worked for all users, then reconfigure exim to use maildir and restart it; reconfigure dovecot to listen to external interfaces and restart.) How I tested: ============= Before trying this on the real server, I set up a matching (same versions of Debian, Exim, and Dovecot) VM using mbox, with a couple of accounts. One using POP3, one using IMAP. The IMAP account was accessed from Claws and from Outlook. The test accounts had perhaps a dozen messages on the server. I tried the conversion procedure, and everything I tried worked flawlessly. (Yes, next time I will move some real inbox files from the live server). What went wrong: ================ I encountered two types of problems here. The first was several dsync warnings (username changed): dsync(example): Warning: Mailbox changes caused a desync. You may want to run dsync again: Remote lost mailbox GUID 21bfa11a81f11763ac150000d09efc50 (maybe it was just deleted?) As I understand it, this can result in some or all messages being downloaded again by clients. My understanding may be wrong. I also don't understand how the mailbox could have changed -- exim4 was stopped, dovecot is only listening on 127.0.0.1, and I am the only user who uses a local mail client on that system, and this was not my account. The second problem I encountered seems to match Debian Bug report logs - #1011238. In part of the discussion of that report, the reporter mentions adding -1 to the command, as shown: dsync -v -u "$U" mirror -1 "mbox:/home/$U/mail:INBOX=/var/mail/$U" While this seemed to eliminate the dsync panic of #1011238, as far as I can tell, no old messages were actually moved from the old mbox files to the new maildirs. At that point I restored the backup mbox files and undid the changes to dovecot and exim4. Current setup: ============== Debian 11.4 Exim 4.94.2-7 dovecot 1:2.3.13+dfsg1-2 The current setup with Dovecot was a successful migration from IMAP-UW in December 2020. Output from dovecot -n (the list of trusted networks has been removed) # 2.3.13 (89f716dc2): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.13 (cdd19fe3) # OS: Linux 5.10.0-16-686-pae i686 Debian 11.4 # Hostname: localhost auth_verbose = yes mail_location = mbox:~/mail:INBOX=/var/mail/%u mail_privileged_group = mail namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { driver = pam } pop3_uidl_format = %08Xv%08Xu protocols = " imap pop3" ssl_cert = </etc/dovecot/dovecot.pem ssl_client_ca_dir = /etc/ssl/certs ssl_dh = # hidden, use -P to show it ssl_key = # hidden, use -P to show it userdb { driver = passwd } Thank you to anyone who read this far. Ken

5 5