CVE-2026-42012 Gnutls: gnutls: certificate validation bypass due to improper handling of uri and srv sans
Remote attackers can bypass certificate validation by crafting specific SANs, enabling service spoofing and potential interception of sensitive data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-42012?
CVE-2026-42012 is a high-severity vulnerability in Cert Manager support for Red Hat OpenShift release 1.17, published on 26 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-295
Which versions are affected by CVE-2026-42012?
How do I fix CVE-2026-42012?
Apply the vendor's patch.
Is CVE-2026-42012 being exploited?
There is no known exploitation of CVE-2026-42012 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-42012, AZL-89187, BELL-CVE-2026-42012, CLSA-2026-1789460699, DEBIAN-CVE-2026-42012, ECHO-abd3-5305-c7ca and 1 more.