---
id: "CVE-2026-114640"
kind: "vulnerability"
aliases: ["CVE-2026-114640"]
title: "Traefik: forged client certificate headers bypass mTLS authentication on HTTP"
severity: "high"
cvss: 8.7
epss: 0.00202
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["ingress-nginx", "kubernetes", "runtime", "traefik"]
not_affected_if: ["default-config", "traefik-3.7.14-or-later", "traefik-below-3.7.0"]
published_at: "2026-10-22T02:16:56+00:00"
first_seen_at: "2026-10-23T21:57:30+00:00"
updated_at: "2026-10-24T07:15:52+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-114640", "first_seen_at": "2026-10-23T21:57:30+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-114640", "first_seen_at": "2026-10-24T07:15:52+00:00"}]
---

# Traefik: forged client certificate headers bypass mTLS authentication on HTTP

Traefik's Kubernetes Ingress-NGINX provider trusts client-supplied Ssl-Client-* headers on its plaintext HTTP router. An unauthenticated attacker can send Ssl-Client-Verify: SUCCESS with a chosen subject and issuer to impersonate any mTLS identity.

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

## How to check

Check the Traefik version is 3.7.0 or later; the flaw is in v3.7.0 before v3.7.14.
Check whether ingress annotations set nginx.ingress.kubernetes.io/ssl-redirect to false together with nginx.ingress.kubernetes.io/auth-tls-pass-certificate-to-upstream to true.

## Fix

Upgrade Traefik to v3.7.14 or later.
Until upgraded, remove ssl-redirect disabling or auth-tls-pass-certificate-to-upstream from affected ingresses.

## Timeline

- 2026-10-23T21:57:30+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-114640
- 2026-10-24T07:15:52+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-114640

## From the sources

Traefik from v3.7.0 before v3.7.14 contains an authentication bypass vulnerability in its Kubernetes Ingress-NGINX provider that forwards client-supplied Ssl-Client-* headers on the plaintext HTTP router. When ssl-redirect is disabled alongside auth-tls-pass-certificate-to-upstream, unauthenticated attackers can send Ssl-Client-Verify: SUCCESS with a chosen certificate subject and issuer to impersonate mTLS identities.

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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_