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.
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History

Fri, 04 Sep 2026 11:45:00 +0000

Type Values Removed Values Added
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.
Title Traefik v3.7.1 crossProviderNamespaces Bypass via Service Middleware
First Time appeared Traefik
Traefik traefik
Weaknesses CWE-639
CPEs cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
Vendors & Products Traefik
Traefik traefik
References
Metrics cvssV4_0

{'score': 7, 'vector': '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'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-04T11:29:58.771Z

Reserved: 2026-09-04T10:59:00.162Z

Link: CVE-2026-85594

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-04T12:17:22.830

Modified: 2026-09-04T12:17:22.830

Link: CVE-2026-85594

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-04T13:45:04Z

Weaknesses