---
id: CVE-2026-112778
title: >-
  Traefik before 2.11.46, 3.6.17, and 3.7.1 Cross-Namespace Resource Reference
  via Kubernetes Annotations
summary: >-
  Traefik before 2.11.46, 3.x before 3.6.17, and 3.7.0 lack namespace validation
  for Ingress and Service annotations in the Kubernetes Ingress provider,
  allowing references to Middlewares, ServersTransports, and TLSOptions in other
  namespa…
severity: medium
cvss: 6.4
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:H/SA:H'
cvssSource: cna
cwe:
  - CWE-862
vendor: traefik
product: traefik
affected:
  - traefik < 2.11.46
  - traefik >= 3.0.0 < 3.6.17
  - traefik >= 3.7.0 < 3.7.1
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-19T21:15:57.381151Z'
published: '2026-10-19'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T21:16:12.196Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-112778'
references:
  - url: 'https://github.com/traefik/traefik/security/advisories/GHSA-rh7m-2m44-x32f'
    label: GitHub Security Advisory (GHSA-rh7m-2m44-x32f)
  - url: >-
      https://www.vulncheck.com/advisories/traefik-before-2.11.46-3.6.17-and-3.7.1-cross-namespace-resource-reference-via-kubernetes-annotations
    label: >-
      VulnCheck Advisory: Traefik before 2.11.46, 3.6.17, and 3.7.1
      Cross-Namespace Resource Reference via Kubernetes Annotations
tags:
  - cve.org
ingestedAt: '2026-10-19T19:38:06.462Z'
---

## Overview

Traefik before 2.11.46, 3.x before 3.6.17, and 3.7.0 lack namespace validation for Ingress and Service annotations in the Kubernetes Ingress provider, allowing references to Middlewares, ServersTransports, and TLSOptions in other namespaces. Attackers able to create or update Ingress or Service resources in one namespace can set router.middlewares or service.serverstransport annotations to obtain another tenant's injected credentials or reuse its client certificates, bypassing namespace-based tenant isolation.

## Affected

- `traefik < 2.11.46`
- `traefik >= 3.0.0 < 3.6.17`
- `traefik >= 3.7.0 < 3.7.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.