CVE-2026-3833 MEDIUM

CVE-2026-3833: Gnutls: gnutls: policy bypass due to case-sensitive nameconstraints comparison

Vendor Red Hat
Product Red Hat Enterprise Linux 6
Weakness CWE-178
Published April 30, 2026
Last update June 30, 2026

CVSS base score

6.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality Low
Integrity Low

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 30, 2026 CVE published
June 30, 2026 Record updated

Related vulnerabilities

04Related CVE