---
id: "CVE-2026-112778"
kind: "vulnerability"
aliases: ["CVE-2026-112778"]
title: "Traefik: Kubernetes Ingress annotations reach other namespaces' credentials and certificates"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "runtime"
products: [{"name": "traefik", "fixed": ["2.11.46"], "affected": "< 2.11.46", "ecosystem": "vendor"}, {"name": "traefik", "fixed": ["3.6.16"], "affected": ">= 3.0.0, < 3.6.16", "ecosystem": "vendor"}, {"name": "traefik", "fixed": [], "affected": "= 3.7.0", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["ingress-controller", "kubernetes", "multi-tenant", "runtime", "traefik"]
not_affected_if: ["kubernetes-provider-disabled", "no-untrusted-namespace-users", "single-tenant-cluster"]
published_at: "2026-10-19T20:17:55+00:00"
first_seen_at: "2026-10-23T21:57:19+00:00"
updated_at: "2026-10-23T22:33:07+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112778", "first_seen_at": "2026-10-23T21:57:19+00:00"}]
---

# Traefik: Kubernetes Ingress annotations reach other namespaces' credentials and certificates

Traefik's Kubernetes Ingress provider does not check namespaces when Ingress or Service annotations reference Middlewares, ServersTransports, or TLSOptions. A user who can create or update Ingress or Service resources in one namespace can reuse another tenant's injected credentials or client certificates.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:traefik affected < 2.11.46 fixed 2.11.46
- vendor:traefik affected >= 3.0.0, < 3.6.16 fixed 3.6.16
- vendor:traefik affected = 3.7.0 fixed ?

## How to check

Compare the running Traefik version against the affected ranges: below 2.11.46, 3.x below 3.6.17, and 3.7.0. Exposed if the Kubernetes Ingress provider serves several tenant namespaces. The sources give no command.

## Fix

Upgrade to Traefik 2.11.46 or 3.6.17 or later. The sources give no fixed version for 3.7.0.

## Timeline

- 2026-10-23T21:57:19+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-112778

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_