CVE-2026-53622
Traefik: HTTP/3 mTLS bypass via exact SNI TLSOptions lookup for wildcard and mixed-case hosts
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | High7.8 | 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 |
| redhat-SADPADP (enrichment) | 3.1 | Critical9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| NVDNVD · Modified | 4.0 | High7.8 | 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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.63% · top 50% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Gogithub.com/traefik/traefikGHSA-9cr8-q42q-g8m7 (opens in a new tab)
- Gogithub.com/traefik/traefik/v2GHSA-9cr8-q42q-g8m7 (opens in a new tab)
- Gogithub.com/traefik/traefik/v3GHSA-9cr8-q42q-g8m7 (opens in a new tab)
References (9)
- https://github.com/traefik/traefik/security/advisories/GHSA-9cr8-q42q-g8m7 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/traefik/traefik/pull/13214 (opens in a new tab)x_refsource_MISC
- https://access.redhat.com/security/cve/CVE-2026-53622 (opens in a new tab)x_refsource_MISCvdb-entryx_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2491924 (opens in a new tab)x_refsource_MISCissue-trackingx_refsource_REDHAT
- 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 (opens in a new tab)x_refsource_MISC
- https://github.com/traefik/traefik/compare/v3.6.17...v3.6.18 (opens in a new tab)x_refsource_MISC
- https://github.com/traefik/traefik/releases/tag/v3.7.3 (opens in a new tab)x_refsource_MISC
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53622.json (opens in a new tab)x_refsource_MISCx_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:62260 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-9cr8-q42q-g8m7 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-53622)Record last updated .