CVE-2026-40203 Affecting dovecot package, versions <2.4.5-r0


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.22% (13th percentile)

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  • Snyk IDSNYK-ALPINE323-DOVECOT-19436028
  • published31 Aug 2026
  • disclosed28 Aug 2026

Introduced: 28 Aug 2026

NewCVE-2026-40203  (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 IMAP compression is enabled, the same compression state is reused across responses in a session, so response sizes depend on both attacker-supplied mail and other mail in the same mailbox. An attacker that can send mail to a user and can also observe the sizes of that user's IMAP traffic can confirm whether the body of a small message matches a guessed text. Recovery of arbitrary unknown content was not demonstrated, but the attack can disclose whether a secret-like message body matches a candidate. Disable IMAP compression. Update to non-vulnerable version. No publicly available exploits are known.

CVSS Base Scores

version 3.1