---
id: CVE-2026-121966
title: Traefik before 2.11.60 and 3.7.16 ForwardAuth NTLM/Negotiate Identity Leak
summary: >-
  Traefik 2.x before 2.11.60 and 3.x before 3.7.16 sends ForwardAuth subrequests
  (and, in 3.7, Ingress NGINX auth-url requests) through an auth-server
  connection pool shared by all clients, exposing connection-bound NTLM or
  Negotiate authe…
severity: high
cvss: 8.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-488
vendor: traefik
product: traefik
affected:
  - traefik < 2.11.60
  - traefik >= 3.0.0 < 3.7.16
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-11-04T18:13:59.569753Z'
published: '2026-11-04'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T18:17:29.572Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-121966'
references:
  - url: 'https://github.com/traefik/traefik/security/advisories/GHSA-hrpp-p4fc-wwf8'
    label: GitHub Security Advisory (GHSA-hrpp-p4fc-wwf8)
  - url: >-
      https://www.vulncheck.com/advisories/traefik-before-2.11.60-and-3.7.16-forwardauth-ntlm-negotiate-identity-leak
    label: >-
      VulnCheck Advisory: Traefik before 2.11.60 and 3.7.16 ForwardAuth
      NTLM/Negotiate Identity Leak
tags:
  - cve.org
ingestedAt: '2026-11-05T21:36:00.482Z'
epss: 0.00333
epssPercentile: 0.26838
---

## Overview

Traefik 2.x before 2.11.60 and 3.x before 3.7.16 sends ForwardAuth subrequests (and, in 3.7, Ingress NGINX auth-url requests) through an auth-server connection pool shared by all clients, exposing connection-bound NTLM or Negotiate authentication. An unauthenticated attacker can reuse another user's authenticated connection, receiving the victim's identity via authResponseHeaders to access backends as that user.

## Affected

- `traefik < 2.11.60`
- `traefik >= 3.0.0 < 3.7.16`

## Remediation

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