---
id: CVE-2026-43964
title: >-
  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.
summary: >-
  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.
severity: low
cvss: 3.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-193
  - CWE-193
vendor: postfix
product: postfix
affected:
  - postfix < 3.8.16
  - 'postfix >= 3.9.0, < 3.9.10'
  - 'postfix >= 3.10.0, < 3.10.9'
patched:
  - postfix 3.10.9
published: '2026-05-04'
updated: '2026-08-06'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-43964'
references:
  - url: 'https://www.mail-archive.com/postfix-announce@postfix.org/msg00110.html'
    label: cve@mitre.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/05/04/30'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://access.redhat.com/errata/RHSA-2026:25930'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:25932'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:26205'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:50963'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:50964'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:51034'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-43964'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2466488'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43964.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
tags:
  - nvd
epss: 0.00511
epssPercentile: 0.42583
ingestedAt: '2026-08-06T13:59:37.127Z'
---

## Overview

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.

## Affected

- `postfix < 3.8.16`
- `postfix >= 3.9.0, < 3.9.10`
- `postfix >= 3.10.0, < 3.10.9`

## Remediation

Upgrade past the affected range:

- `postfix 3.10.9`