Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-85594

CVE-2026-85594HIGH

Traefik v3.7.1 crossProviderNamespaces Bypass via Service Middleware

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   P   L   N   H   N   N    7.0   .0048   39.0     —

AFFECTED
  Product  Versions  Fixed
  traefik  3.7.1 –   —

TIMELINE
  Sep 4   Reserved by VulnCheck
  Sep 4   Published (CNA: VulnCheck)
  Sep 16  EXPLOIT PUBLISHED — CVE-2026-85594 (traefik). Public exploit reference added.

CWE-639 · CNA: VulnCheck · CVSS v4.0 · 2 references · NVD status: Analyzed

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
September 4, 2026	Reserved	Reserved by VulnCheck
September 4, 2026	Published	Published (CNA: VulnCheck)
September 16, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-85594 (traefik). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
traefik	traefik	—	3.7.1	—

Weaknesses

CWE-639

References (2)

https://github.com/traefik/traefik/security/advisories/GHSA-m6wx-622r-48r9 [Exploit, Patch, Vendor Advisory]
https://www.vulncheck.com/advisories/traefik-3.7.1-crossprovidernamespaces-bypass-via-service-middleware [Third Party Advisory]

Authoritative record: CVE-2026-85594 at cve.org

Vendors: traefik

Weaknesses: CWE-639

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-85594 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.