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Advisory record · GHSA-qqjf-53cj-pwvv

Traefik HTTP/3 Backend NTLM Connection Reuse

CVSS 9.1 CriticalCriticalEPSS 0.0060 · 49th percentile

Critical, because:

  • CVSS score 9.1: 9.0 or more.

How we decide what’s critical

Published by the GitHub Advisory Database at 10 Sept 2026, 23:04 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
github.com/traefik/traefik/v3Go>=3.0.0, <3.7.133.7.13
github.com/traefik/traefik/v2Go>=2.11.0, <2.11.572.11.57
Identifiers
GHSA-qqjf-53cj-pwvv · CVE-2026-88007 · GO-2026-6466
Weakness (CWE)
CWE-287 · CWE-863
Tags
Published
10 Sept 2026
Updated
17 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Traefik v3 from 3.0.0 before 3.7.13 and v2 from 2.11.0 before 2.11.57 are affected. When HTTP/3 is enabled on an entrypoint and a backend uses connection-bound NTLM or Negotiate authentication with keep-alive, an unauthenticated HTTP/3 client can be assigned a backend connection already authenticated as another user, reading that user's data and performing actions as them. Upgrade to Traefik 3.7.13 or 2.11.57. The source gives no workaround other than upgrading.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
9.1 Critical 4.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0060, the 49th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 7 Sept 2026, 09:24 UTC Published by the maintainers as a GitHub repository advisory
  2. 31 Oct 2026, 14:13 UTC First seen by agentprime
  3. 31 Oct 2026, 14:13 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.