Traefik: HTTP/3 mTLS bypass via exact SNI TLSOptions lookup for wildcard and mixed-case hosts_CVE-2026-53622

{
    "lastseen": "",
    "description": "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 \u2014 which may not require client certificates \u2014 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": "2026-06-23T19:13:28.844Z",
    "type": "cve",
    "title": "Traefik: HTTP/3 mTLS bypass via exact SNI TLSOptions lookup for wildcard and mixed-case hosts",
    "source": "GitHub_M",
    "references": "https://github.com/traefik/traefik/security/advisories/GHSA-9cr8-q42q-g8m7\nhttps://github.com/traefik/traefik/releases/tag/v3.7.3",
    "id": "CVE-2026-53622",
    "bulletinFamily": "",
    "cwe": [
        "CWE-288"
    ],
    "cvelist": null,
    "sourceData": "traefik traefik < 3.7.3",
    "sourceHref": "",
    "cvss": {
        "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",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
        "baseSeverity": "",
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        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
            "baseSeverity": "",
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            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "traefik",
    "version": "< 3.7.3",
    "vendor": "traefik",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}