Improper Validation of Specified Quantity in Input Affecting gnutls28 package, versions <3.6.13-2ubuntu1.12+esm3


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.42% (34th percentile)

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  • Snyk IDSNYK-UBUNTU2004-GNUTLS28-16355252
  • published15 Jul 2026
  • disclosed26 May 2026

Introduced: 26 May 2026

CVE-2026-42013  (opens in a new tab)
CWE-1284  (opens in a new tab)

How to fix?

Upgrade Ubuntu:20.04 gnutls28 to version 3.6.13-2ubuntu1.12+esm3 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream gnutls28 package and not the gnutls28 package as distributed by Ubuntu. See How to fix? for Ubuntu:20.04 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1