CVE-2026-42013
HighCVSS 8.2Exploitation Probability (EPSS)
Low risk34th percentile - higher than 34% of all known CVEs
Summary
A flaw was found in GnuTLS where an oversized Subject Alternative Name (SAN) during certificate validation could cause incorrect fallback to checking the Common Name (CN) field. This allows a remote attacker to bypass proper certificate validation, potentially leading to spoofing or man-in-the-middle attacks.
Risk Assessment
The organization is at risk of communication interception by an attacker who can impersonate a trusted server, potentially leading to data theft or compromise of TLS connection integrity.
Recommendation
Immediately update the GnuTLS library to a patched version and review certificate validation configuration in applications using this library.
Original NVD description (English source)
A flaw was found in gnutls. When validating certificates, an oversized Subject Alternative Name (SAN) could cause the validation process to incorrectly fall back to checking the Common Name (CN) field. This could allow a remote attacker to bypass proper certificate validation, potentially leading to spoofing or man-in-the-middle attacks.