CVE-2026-43964

Publication date 5 May 2026

Last updated 13 May 2026

Ubuntu priority

Cvss 3 Severity Score

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.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
postfix	26.04 LTS resolute	Fixed 3.10.6-4ubuntu2.1
	25.10 questing	Fixed 3.10.2-1ubuntu2.1
	24.04 LTS noble	Fixed 3.8.6-1ubuntu0.1
	22.04 LTS jammy	Fixed 3.6.4-1ubuntu1.4
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Needs evaluation

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
postfix	Upstream: https://www.postfix.org/announcements/postfix-3.11.2.html

Severity score breakdown

Parameter	Value
Base score	3.7 · Low
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	Low
Vector	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

References

Related Ubuntu Security Notices (USN)

USN-8253-1
Postfix vulnerability
7 May 2026