Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-2964 (Bug ID) Vulnerability type: CWE-120 Vulnerable version: 2.0.14 - 2.3.5 Vulnerable component: fts, pop3-uidl-plugin Report confidence: Confirmed Researcher credits: Found in internal testing Solution status: Fixed by Vendor Fixed version: 2.3.5.1, 2.2.36.3 Vendor notification: 2019-02-05 Solution date: 2019-03-21 Public disclosure: 2019-03-28 CVE reference: CVE-2019-7524 CVSS: 3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C (8.8) Vulnerability Details: When reading FTS or POP3-UIDL header from dovecot index, the input buffer size is not bound, and data is copied to target structure causing stack overflow.

Risk: This can be used for local root privilege escalation or executing arbitrary code in dovecot process context. This requires ability to directly modify dovecot indexes. Steps to reproduce: Produce dovecot.index.log entry that creates an FTS header which has more than 12 bytes of data. Trigger dovecot indexer-worker or run doveadm index. Dovecot will crash.

Mitigations: Since 2.3.0 dovecot has been compiled with stack smash protection, ASLR, read-only GOT tables and other techniques that make exploiting this bug much harder.

Solution: Operators should update to the latest Patch Release. The only workaround is to disable FTS and pop3-uidl plugin.

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