{"id":"CVE-2026-53622","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-53622","generatedAt":"2026-10-28T08:10:26.270Z","title":"Versions prior to 3.7.3, 3.6.18, and 2.11.51 have a critical vulnerability in Traefik's HTTP/3 (QUIC) TLS configuration selection that allows unauthenticated clients to bypass router-specific mTLS enforcement.","description":"Traefik is an HTTP reverse proxy and load balancer. Versions prior to 3.7.3, 3.6.18, and 2.11.51 have 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 versions 3.7.3, 3.6.18, and 2.11.51.","published":"2026-06-23T20:16:49.000Z","lastModified":"2026-09-02T13:18:02.000Z","status":"Modified","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"4.0","score":7.8,"severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-288","CWE-289"],"affected":["traefik/traefik"],"epss":{"score":0.00629,"percentile":0.49925,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.63%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-53622","source":"security-advisories@github.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2491924","source":"security-advisories@github.com"},{"url":"https://community.traefik.io/t/new-security-update-for-traefik-2-11-2-11-48-3-6-3-6-19-and-3-7-3-7-3/29917","source":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/compare/v3.6.17...v3.6.18","source":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/pull/13214","source":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/releases/tag/v3.7.3","tags":["Patch","Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/security/advisories/GHSA-9cr8-q42q-g8m7","tags":["Exploit","Mitigation","Patch","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53622.json","source":"security-advisories@github.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:62260","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/security/cve/CVE-2026-53622","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2491924","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53622.json","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-53622","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}