TI-2026-38669 Aliases CVE-2026-53622 GHSA-9cr8-q42q-g8m7

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

MEDIUM 41CWE-288Published 2026-06-23 · Updated 2026-09-02

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: Security bypass
Confidentiality · integrity · availability: None · None · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-288.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00629 50th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed traefik (traefik): 3.7.3, 3.6.18, 2.11.51github.com/traefik/traefik/v3 (Go): 3.7.3, 3.6.18+1 more productRed Hat: 1 advisory

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
traefik	traefik	3.7.0 to before 3.7.3; 3.0.0 to before 3.6.18; before 2.11.51	3.7.3, 3.6.18, 2.11.51	Patch available	CNA
—	github.com/traefik/traefik/v3 (Go)	3.7.0 to before 3.7.3	3.7.3	Patch available	GHSA-9cr8-q42q-g8m7
—	github.com/traefik/traefik/v2 (Go)	before 2.11.51	2.11.51	Patch available	GHSA-9cr8-q42q-g8m7
—	github.com/traefik/traefik (Go)	up to 1.7.34	—	No fix listed	GHSA-9cr8-q42q-g8m7
—	github.com/traefik/traefik/v3 (Go)	before 3.6.18	3.6.18	Patch available	GHSA-9cr8-q42q-g8m7

traefik Vendortraefik Affected 3.7.0 to before 3.7.3; 3.0.0 to before 3.6.18; before 2.11.51 Fixed in 3.7.3, 3.6.18, 2.11.51 Patch available CNA
github.com/traefik/traefik/v3 (Go) Vendor— Affected 3.7.0 to before 3.7.3 Fixed in 3.7.3 Patch available GHSA-9cr8-q42q-g8m7
github.com/traefik/traefik/v2 (Go) Vendor— Affected before 2.11.51 Fixed in 2.11.51 Patch available GHSA-9cr8-q42q-g8m7
github.com/traefik/traefik (Go) Vendor— Affected up to 1.7.34 Fixed in — No fix listed GHSA-9cr8-q42q-g8m7
github.com/traefik/traefik/v3 (Go) Vendor— Affected before 3.6.18 Fixed in 3.6.18 Patch available GHSA-9cr8-q42q-g8m7

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:traefik:traefik::::::::	before 3.7.3	Vulnerable	traefik

cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:* Versions before 3.7.3 Vulnerable ·traefik

Remediation

Fix · CNA traefik (traefik) Fixed in 3.7.3, 3.6.18, 2.11.51
Fix · GHSA-9cr8-q42q-g8m7 github.com/traefik/traefik/v3 (Go) Fixed in 3.7.3 Advisory →
Fix · GHSA-9cr8-q42q-g8m7 github.com/traefik/traefik/v2 (Go) Fixed in 2.11.51 Advisory →
Fix · GHSA-9cr8-q42q-g8m7 github.com/traefik/traefik/v3 (Go) Fixed in 3.6.18 Advisory →

Red Hat 1 advisory

RHSA-2026:62260 Released 2026-09-01 · Red Hat rating Important
Red Hat OpenShift Dev Spaces 3.30.0 Release.
- Red Hat OpenShift Dev Spaces 3.30 registry.redhat.io/devspaces/code-rhel9, registry.redhat.io/devspaces/configbump-rhel9, registry.redhat.io/devspaces/dashboard-rhel9 +7

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat OpenShift Dev Spaces 3.30	Fixed	RHSA-2026:62260

Not affected: 1 product

Red Hat OpenShift Dev Spaces 3.30

Timeline

2026-10-02 Threatist record created from CVE-2026-53622
2026-10-03 Alias added: GHSA-9cr8-q42q-g8m7
2026-10-29 EPSS moved to the 50th–90th percentile

References

Other 8

TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
TI-2023-25774 Uncontrolled Resource Consumption in Traefik CVSS 3.1HIGH 7.5
TI-2025-40914 Traefik doesn't Prevent Path Normalization Bypass in Router + Middleware Rules CVSS 4.0MEDIUM 6.9
TI-2022-07529 Authorization header displayed in the debug logs CVSS 3.1MEDIUM 6.5
TI-2024-30459 HTTP client can remove the X-Forwarded headers in Traefik CVSS 3.1CRITICAL 9.8
TI-2026-60261 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect CVSS 4.0CRITICAL 9.3

See all 83 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences