CVE-2026-85594
Traefik v3.7.1 crossProviderNamespaces Bypass via Service Middleware
- State
- Published
- Severity
- 7.0 High
- Published
- Sep 4, 2026
- Updated
- Oct 8, 2026
- Reserved
- Sep 4, 2026
Description
Traefik versions from v3.7.1 fail to enforce crossProviderNamespaces restrictions on the traefik.ingress.kubernetes.io/service.middlewares Service annotation in the Kubernetes Ingress provider. A namespace-limited tenant excluded from the allowlist can attach an operator-owned middleware to its Service, and if that middleware injects backend credentials, recover them at a controlled backend.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 7.0 High | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N | VulnCheck |
Weaknesses
- CWE-639 Authorization Bypass Through User-Controlled Key
Affected Products
| Product | Versions |
|---|---|
traefiktraefik |
|
References
- GitHub Security Advisory (GHSA-m6wx-622r-48r9)vendor-advisory
- VulnCheck Advisory: Traefik v3.7.1 crossProviderNamespaces Bypass via Service Middlewarethird-party-advisory
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