CVE-2026-67693
lowAn issue in gnutls v.3.8.13 allows an attacker to obtain sensitive information via failing to reject end-entity X.509 certificates that contain a contradictory…
GnuTLS v3.8.13 does not reject end-entity X.509 certificates that contain a contradictory combination of Key Usage (KU) and Extended Key Usage (EKU). NOTE: the Supplier does not consider this an actionable security vulnerability because of its "threat model doesn't consider attacks only possible by modifying anything within the trust boundary (private keys, trusted certificate authorities and their issued certificates including intermediate CAs, etc.)" policy.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://gist.github.com/lkloliver/6fbfc191bc6163942c8017551ac3f238 cve@mitre.org
- https://gitlab.com/gnutls/gnutls/-/blob/3.8.13/lib/x509/verify.c#L1119-1178 cve@mitre.org
- https://gitlab.com/gnutls/gnutls/-/blob/e2169a87c7fb91935c2845088204b102baed4c5f/SECURITY.... cve@mitre.org
- https://gitlab.com/gnutls/gnutls/-/work_items/1642 cve@mitre.org
- https://gitlab.com/gnutls/gnutls/-/work_items/1965 cve@mitre.org
- https://github.com/lkloliver/poc/tree/main/CVE-2026-67693 af854a3a-2127-422b-91ae-364da2661108