CVE-2026-33263 Affecting dovecot package, versions <2.4.5-r0


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.29% (22nd percentile)

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  • Snyk IDSNYK-ALPINE323-DOVECOT-19436026
  • published31 Aug 2026
  • disclosed28 Aug 2026

Introduced: 28 Aug 2026

NewCVE-2026-33263  (opens in a new tab)

How to fix?

Upgrade Alpine:3.23 dovecot to version 2.4.5-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream dovecot package and not the dovecot package as distributed by Alpine. See How to fix? for Alpine:3.23 relevant fixed versions and status.

When mail_max_userip_connections is set (default 10) and reached, submission-login can crash with epoll() panic caused by file descriptor handling issues. If running in high-security mode (default for community releases), only the new submission connection gets terminated. If running in high-performance mode (default for Pro releases), all connections handled by the submission-login process will be terminated. The crashes can cause failure for user to send a message, or it can cause duplicate messages to be sent. If TLS is not used (in the backend server processing the submission), duplicate deliveries cannot happen, because the crash can only happen at AUTH stage. Limit the number of connections handled by single submission-login process. This has a performance impact though. Update to non-vulnerable version. No publicly available exploits are known.

CVSS Base Scores

version 3.1