---
id: CVE-2026-85594
title: >-
  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
summary: >-
  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 th…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-639
  - CWE-1220
vendor: traefik
product: traefik
affected:
  - traefik < 3.7.11
patched:
  - traefik 3.7.11
published: '2026-09-04'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T20:42:53.890'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85594'
references:
  - url: 'https://github.com/traefik/traefik/security/advisories/GHSA-m6wx-622r-48r9'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/traefik-3.7.1-crossprovidernamespaces-bypass-via-service-middleware
    label: disclosure@vulncheck.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-85594.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-85594'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2529861'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-85594'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85594'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00262
epssPercentile: 0.18367
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-08T14:47:22.510684Z'
scores:
  nvd: 9.8
  cna: 7
  vendor: 7.7
ingestedAt: '2026-09-08T15:33:26.960Z'
---

## Overview

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.

## Affected

- `traefik < 3.7.11`

## Remediation

Upgrade past the affected range:

- `traefik 3.7.11`

## Vendor advisories

- **Red Hat VEX** · Important · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-85594.json)