# CVE-2026-67693: CVE-2026-67693

Status: published. Published: 2026-10-08. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- n/a / n/a: Version not specified (affected). Source: CNA: mitre

## Severity and prioritization

- CVSS 3.1: 3.7 (low); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N; source: ADP: CISA-ADP

- CVSS 3.1: 3.7 (low); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N; source: NVD: 134c704f-9b21-4f2e-91b3-4a467353bcc0

- CISA KEV: No listing in collected sources

- EPSS: 0.15% as of 2026-11-03; percentile 4.31%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-367

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://gitlab.com/gnutls/gnutls/-/blob/3.8.13/lib/x509/verify.c#L1119-1178 (CNA: mitre)

- https://gist.github.com/lkloliver/6fbfc191bc6163942c8017551ac3f238 (CNA: mitre)

- https://gitlab.com/gnutls/gnutls/-/work_items/1642 (CNA: mitre)

- https://gitlab.com/gnutls/gnutls/-/work_items/1965 (CNA: mitre)

- https://gitlab.com/gnutls/gnutls/-/blob/e2169a87c7fb91935c2845088204b102baed4c5f/SECURITY.md (CNA: mitre)

- https://github.com/lkloliver/poc/tree/main/CVE-2026-67693 (ADP: CVE)

- 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.md (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)

## Provenance

- CNA: mitre: https://www.cve.org/CVERecord?id=CVE-2026-67693; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-67693; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-67693; retrieved 2026-11-04; source updated Not reported

Revision: f38fde0854d200f0f15bc6f9965acbb28cfcc26b6871ee1987031dae49c10b5f

Canonical: https://y2.dev/cve/CVE-2026-67693

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