CVE-2026-42011
Published: 07 May 2026
Summary
CVE-2026-42011 is a high-severity Improper Certificate Validation (CWE-295) vulnerability. Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Adversary-in-the-Middle (T1557); ranked at the 4.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-28386
Vulnerability details
A flaw was found in gnutls. This vulnerability occurs because permitted name constraints were incorrectly ignored when previous Certificate Authorities (CAs) only had excluded name constraints. A remote attacker could exploit this to bypass critical name constraint checks during certificate…
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validation. This bypass could lead to the acceptance of invalid certificates, potentially enabling spoofing or man-in-the-middle attacks against affected systems.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct certificate validation bypass in TLS library enables adversary-in-the-middle attacks via spoofed certificates.
CVEs Like This One
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
When certificates are used to establish component provenance, the control requires correct certificate validation procedures.
Mandates approved trust anchors and issuance policies, directly preventing acceptance of unvalidated or untrusted certificates.
Correct system time is required for proper enforcement of certificate notBefore/notAfter dates and time-based revocation checks.