Improper Certificate Validation in GnuTLS - CVE-2026-3833
Published: April 30, 2026
Vulnerability identifier: #VU128572
CSH Severity: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-3833
CWE-ID: CWE-295
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
GnuTLS
GnuTLS
Software vendor:
GnuTLS
GnuTLS
Description
The vulnerability allows a remote attacker to bypass name constraints validation.
The vulnerability exists due to improper certificate validation in name constraints processing when comparing domain names in certificates. A remote attacker can present a specially crafted certificate to bypass name constraints validation.
This issue affects excluded name constraints because domain name comparison was performed case-sensitively, contrary to RFC 5280 section 7.2.
Remediation
Install security update from vendor's website.