CVE-2026-3833

MEDIUM

Gnutls: gnutls: policy bypass due to case-sensitive nameconstraints comparison

Title source: cna

Description

A flaw was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of `nameConstraints` labels, specifically for `dNSName` (DNS) or `rfc822Name` (email) constraints within `excludedSubtrees` or `permittedSubtrees`. A remote attacker can exploit this by crafting a leaf certificate with casing differences in the Subject Alternative Name (SAN), leading to a policy bypass where a certificate that should be rejected is instead accepted. This could result in unauthorized access or information disclosure.

References (17)

Core 17

Core References

Vdb Entry, X_Refsource_Redhat vdb-entry x_refsource_redhat

https://access.redhat.com/security/cve/CVE-2026-3833

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:20612

https://access.redhat.com/errata/RHSA-2026:20612

Vendor Advisory vendor-advisory x_refsource_redhat

https://access.redhat.com/errata/RHSA-2026:20613

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:26319

https://access.redhat.com/errata/RHSA-2026:26319

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:26409

https://access.redhat.com/errata/RHSA-2026:26409

https://gitlab.com/gnutls/gnutls/-/issues/1803

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:29197

https://access.redhat.com/errata/RHSA-2026:29197

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:30004

https://access.redhat.com/errata/RHSA-2026:30004

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:30849

https://access.redhat.com/errata/RHSA-2026:30849

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:30850

https://access.redhat.com/errata/RHSA-2026:30850

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:32962

https://access.redhat.com/errata/RHSA-2026:32962

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:33125

https://access.redhat.com/errata/RHSA-2026:33125

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:20611

https://access.redhat.com/errata/RHSA-2026:20611

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:13274

https://access.redhat.com/errata/RHSA-2026:13274

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:41921

https://access.redhat.com/errata/RHSA-2026:41921

Issue Tracking, X_Refsource_Redhat issue-tracking x_refsource_redhat

RHBZ#2445763

https://bugzilla.redhat.com/show_bug.cgi?id=2445763

Vendor Advisory vendor-advisory x_refsource_redhat

RHSA-2026:43575

https://access.redhat.com/errata/RHSA-2026:43575

Scores

CVSS v3 6.5

EPSS 0.0056

EPSS Percentile 43.7%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation poc

Automatable yes

Technical Impact partial

Details

CWE

CWE-178

Status published

Products (42)

gnu/gnutls

Red Hat/Red Hat Discovery 2 1782159791

Red Hat/Red Hat Discovery 2 1782166952

Red Hat/Red Hat Enterprise Linux 10

Red Hat/Red Hat Enterprise Linux 10 0:3.8.10-4.el10_2

Red Hat/Red Hat Enterprise Linux 10.0 Extended Update Support 0:3.8.9-9.el10_0.19

Red Hat/Red Hat Enterprise Linux 6

Red Hat/Red Hat Enterprise Linux 7

Red Hat/Red Hat Enterprise Linux 7 Extended Lifecycle Support 0:3.3.29-9.el7_9.2

Red Hat/Red Hat Enterprise Linux 8

... and 32 more

Published Apr 30, 2026

Tracked Since Apr 30, 2026