---
id: "CVE-2026-114641"
kind: "vulnerability"
aliases: ["CVE-2026-114641"]
title: "Traefik: race in NTLM and Kerberos backend auth lets remote requests crash it"
severity: "medium"
cvss: 6.3
epss: 0.00256
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["kubernetes", "runtime", "self-hosted", "traefik", "windows-backends"]
not_affected_if: ["default-config", "no-ntlm-or-kerberos-backends"]
published_at: "2026-10-22T02:16:57+00:00"
first_seen_at: "2026-10-23T21:57:30+00:00"
updated_at: "2026-10-25T04:01:20+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-114641", "first_seen_at": "2026-10-23T21:57:30+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-114641", "first_seen_at": "2026-10-24T07:15:52+00:00"}]
---

# Traefik: race in NTLM and Kerberos backend auth lets remote requests crash it

Traefik 2.11.x before 2.11.58 and 3.x before 3.7.14 read and write a per-connection sticky round tripper slot without locking when handling NTLM or Kerberos (Negotiate) backend authentication. A remote attacker sending concurrent HTTP/2 or HTTP/3 requests over one connection can break connection-bound authentication or crash Traefik.

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

## How to check

- Run `traefik version` or check the image tag and confirm whether it is below `2.11.58` or below `3.7.14`.
- Check whether any router forwards to a backend using NTLM or Negotiate (Kerberos) authentication.

## Fix

- Upgrade Traefik 2.11.x to `2.11.58` or later.
- Upgrade Traefik 3.x to `3.7.14` or later.

## Timeline

- 2026-10-23T21:57:30+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-114641
- 2026-10-24T07:15:52+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-114641

## From the sources

Traefik 2.11.x before 2.11.58 and 3.x before 3.7.14 contains a race condition in NTLM and Kerberos (Negotiate) backend authentication, where the per-connection sticky round tripper slot is read and written without synchronization. Remote attackers can send concurrent HTTP/2 or HTTP/3 requests over one connection to orphan backend connections, break connection-bound authentication, or crash Traefik.

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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_