CVE-2026-42011

Publication date 7 May 2026

Last updated 16 July 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

7.4 · High

Score breakdown

Description

A flaw was found in gnutls. This vulnerability occurs because permitted name constraints were incorrectly ignored when previous Certificate Authorities (CAs) only had excluded name constraints. A remote attacker could exploit this to bypass critical name constraint checks during certificate validation. This bypass could lead to the acceptance of invalid certificates, potentially enabling spoofing or man-in-the-middle attacks against affected systems.

Read the notes from the security team

Status

Package Ubuntu Release Status
gnutls28 26.04 LTS resolute
Fixed 3.8.12-2ubuntu1.1
25.10 questing
Fixed 3.8.9-3ubuntu2.2
24.04 LTS noble
Fixed 3.8.3-1.1ubuntu3.6
22.04 LTS jammy
Fixed 3.7.3-4ubuntu1.9
20.04 LTS focal
Fixed 3.6.13-2ubuntu1.12+esm3
18.04 LTS bionic
Fixed 3.5.18-1ubuntu1.6+esm4
16.04 LTS xenial
Not affected

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Notes

mrmajumder

xenial is not-affected, the vulnerable empty-permitted intersection short-circuit was introduced after 3.4.10.

Patch details

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

Package Patch details
gnutls28

Severity score breakdown

CVSS version: CVSS v3.0

Base score 7.4 · High

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

Related Ubuntu Security Notices (USN)

Other references

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