{"id":"CVE-2026-88647","published":"2026-10-08T17:17:17.783","lastModified":"2026-10-10T03:17:08.620","description":"A hostname verification bypass in GnuTLS v3.8.13 allows attackers to circumvent the Common Name fallback mechanism and eavesdrop on communications via a crafted certificate.","cvssScore":9.1,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","cwes":["CWE-297"],"vendors":[],"products":[],"references":[{"url":"https://gist.github.com/lkloliver/f98ec3de1a871fdfc02b70b8b9ba7642","tags":[]},{"url":"https://gitlab.com/gnutls/gnutls/-/issues/1802","tags":[]},{"url":"https://gitlab.com/gnutls/gnutls/-/issues/1802","tags":[]}],"exploitRefs":[{"url":"https://gist.github.com/lkloliver/f98ec3de1a871fdfc02b70b8b9ba7642","tags":[]}],"hasPoc":true,"ai":{"summary":"GnuTLS v3.8.13 contains a hostname verification bypass flaw that allows attackers to skip certificate validation checks and eavesdrop on encrypted communications. This vulnerability specifically affects the Common Name fallback mechanism, making it possible for attackers to use crafted certificates to impersonate legitimate servers.","exploitability":"Exploitation is relatively straightforward with a pre-existing certificate that includes a valid Subject Alternative Name but omits the Common Name field, requiring minimal setup and no privileged access.","blast_radius":"The impact could be severe across all systems using GnuTLS v3.8.13 for TLS connections, potentially allowing widespread eavesdropping on sensitive communications including web traffic, API calls, and database connections.","remediation":"Upgrade to GnuTLS version 3.8.14 or later to address this hostname verification bypass vulnerability.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["tls","certificate","mitm","encryption","gnutls"],"model":"garnet-coder","analyzedAt":"2026-10-13T08:48:45.320Z"}}