CVE-2026-40203 Affecting dovecot23-backend-mysql package, versions <2.3.21.1-150200.76.1


Severity

Recommended
medium

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.26% (16th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-SLES157-DOVECOT23BACKENDMYSQL-20255924
  • published29 Sept 2026
  • disclosed14 Sept 2026

Introduced: 14 Sep 2026

CVE-2026-40203  (opens in a new tab)

How to fix?

Upgrade SLES:15.7 dovecot23-backend-mysql to version 2.3.21.1-150200.76.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream dovecot23-backend-mysql package and not the dovecot23-backend-mysql package as distributed by SLES. See How to fix? for SLES:15.7 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