{"id":"CVE-2026-53622","aliases":["GHSA-9cr8-q42q-g8m7"],"url":"https://o3.security/vulnerability/CVE-2026-53622","summary":"Traefik: HTTP/3 mTLS bypass via exact SNI TLSOptions lookup for wildcard and mixed-case hosts","details":"Traefik is an HTTP reverse proxy and load balancer. Prior to 3.7.3, there is a critical vulnerability in Traefik's HTTP/3 (QUIC) TLS configuration selection that allows unauthenticated clients to bypass router-specific mTLS enforcement. When HTTP/3 is enabled on an entrypoint, the TLS handshake selects the applicable TLS configuration through an exact, case-sensitive lookup on the SNI value, which fails to match wildcard host patterns (e.g., *.example.com) or case variants of the configured hostname. Because the handshake falls back to the default TLS configuration — which may not require client certificates — a client can complete the QUIC handshake without presenting a certificate, while the subsequent HTTP routing layer still dispatches the request to a backend protected by a router-specific mTLS policy. The issue affects deployments where HTTP/3 is enabled, a router uses a wildcard Host rule or case-insensitive hostname matching, a router-specific TLSOptions enforces client certificate authentication, and UDP access to the entrypoint is reachable by an attacker. This vulnerability is fixed in 3.7.3.","published":"2026-06-23T19:13:28.844Z","modified":"2026-08-07T11:51:23.342591662Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"Traefik","fixedVersion":"3.7.3"},{"ecosystem":"Go","name":"github.com/traefik/traefik/v2","fixedVersion":null},{"ecosystem":"Go","name":"github.com/traefik/traefik","fixedVersion":null}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/traefik/traefik/releases/tag/v3.7.3"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53622.json"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-53622"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53622.json"},{"type":"ADVISORY","url":"https://github.com/traefik/traefik/security/advisories/GHSA-9cr8-q42q-g8m7"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53622"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2491924"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:51:23.342591662Z"}}