Off-by-one Error Affecting postfix package, versions <3.4.13-0ubuntu1.4+esm1


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.42% (34th percentile)

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  • Snyk IDSNYK-UBUNTU2004-POSTFIX-16421850
  • published10 Jun 2026
  • disclosed4 May 2026

Introduced: 4 May 2026

CVE-2026-43964  (opens in a new tab)
CWE-193  (opens in a new tab)

How to fix?

Upgrade Ubuntu:20.04 postfix to version 3.4.13-0ubuntu1.4+esm1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream postfix package and not the postfix package as distributed by Ubuntu. See How to fix? for Ubuntu:20.04 relevant fixed versions and status.

Postfix before 3.8.16, 3.9 before 3.9.10, and 3.10 before 3.10.9 sometimes allows a buffer over-read and process crash via an enhanced status code that lacks text after the third number.

CVSS Base Scores

version 3.1