Gnutls: gnutls: certificate validation bypass due to improper handling of uri and srv sans (CVE-2026-42012)

Why this deserves its current priority

CVSS is 7.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps gnutls (generic), Red Hat/gnutls (generic), Red Hat/openshift/ose-rhel-coreos-8 (generic), Red Hat/openshift/ose-rhel-coreos-9 (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
gnutlsgeneric	0	Not reported
Red Hat/gnutlsgeneric	*	Not reported
Red Hat/openshift/ose-rhel-coreos-8generic	*	Not reported
Red Hat/openshift/ose-rhel-coreos-9generic	*	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for gnutls, Red Hat/gnutls, Red Hat/openshift/ose-rhel-coreos-8.
Review the reported fix. Source-reported workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Evidence timeline and material changes

Published upstream
May 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Nov 3, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jun 24, 2026

Sources and claim methodology

Upstream source description

A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted certificate that contains Uniform Resource Identifier (URI) or Service (SRV) Subject Alternative Names (SANs). This could cause the certificate validation process to incorrectly fall back to checking DNS hostnames against the Common Name (CN), potentially allowing the attacker to spoof legitimate services or intercept sensitive information.

Quoted source text, attributed separately from HOL analysis.

Gnutls: gnutls: certificate validation bypass due to improper handling of uri and srv sansCVE-2026-42012