This vulnerability in gnutls affects certificate validation by mishandling oversized SAN fields. When the SAN is too large, the validation logic falls back to the CN field, which is less secure and can be manipulated. This improper validation can be exploited remotely to bypass certificate checks, undermining the trust model of TLS connections. The CVSS 3.1 score of 8.2 reflects the high impact on confidentiality and integrity without requiring privileges or user interaction. Red Hat Enterprise Linux 10 is affected, but no specific affected versions or patch information are currently detailed in the advisory.

The vulnerability allows remote attackers to bypass proper certificate validation, which could lead to spoofing or man-in-the-middle attacks. This compromises the confidentiality and integrity of communications relying on TLS certificates validated by gnutls on affected systems. There is no indication of availability impact. No known exploits in the wild have been reported so far.

Patch status is not yet confirmed — check the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-42013 for current remediation guidance. Until an official fix is released, users should monitor the advisory for updates. No vendor-provided temporary mitigations or workarounds are currently documented.