CVE-2026-42391 Affecting dovecot package, versions <1:2.4.5+dfsg1-1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.38% (31st percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-DOVECOT-19424951
  • published29 Aug 2026
  • disclosed28 Aug 2026

Introduced: 28 Aug 2026

NewCVE-2026-42391  (opens in a new tab)

How to fix?

Upgrade Debian:unstable dovecot to version 1:2.4.5+dfsg1-1 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 Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by the same process. This can cause degradation or denial of service for IMAP logins. Limit the number of connections handled by a single imap-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