CVE-2026-88647
mediumA hostname verification bypass in GnuTLS v3.8.13 allows attackers to circumvent the Common Name fallback mechanism and eavesdrop on communications via a crafte…
GnuTLS v3.8.13 can perhaps unexpectedly trust a certificate on the basis of Common Name when Subject Alternative Name has an SRV otherName (1.3.6.1.5.5.7.8.7) whose value is an OCTET STRING. 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:H/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/f98ec3de1a871fdfc02b70b8b9ba7642 cve@mitre.org
- https://gitlab.com/gnutls/gnutls/-/blob/e2169a87c7fb91935c2845088204b102baed4c5f/SECURITY.... cve@mitre.org
- https://gitlab.com/gnutls/gnutls/-/issues/1802 cve@mitre.org
- https://gitlab.com/gnutls/gnutls/-/work_items/1965 cve@mitre.org
- https://github.com/lkloliver/poc/tree/main/CVE-2026-88647 af854a3a-2127-422b-91ae-364da2661108