CVE-2026-88007 Traefik HTTP/3 Backend NTLM Connection Reuse
Attackers can reuse authenticated backend connections to read victim data and act as victims when HTTP/3 and NTLM are enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-88007?
CVE-2026-88007 is a critical authentication bypass vulnerability in Traefik Traefik, published on 10 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.0 until 2.11.57 and 3.7.13, the HTTP/3 entrypoint ConnContext does not call service.AddTransportOnContext, so kerberosRoundTripper uses a shared backend transport instead of a transport dedicated to each frontend connection. With HTTP/3 enabled, a backend using connection-bound NTLM or Negotiate authentication, and backend keep-alive, an unrelated client can reuse a backend connection authenticated for a victim, read victim-only data, and act as that victim without the victim credentials. This issue is fixed in 2.11.57 and 3.7.13.
Which versions are affected by CVE-2026-88007?
7 open source packages ship an affected version, including github.com/traefik/traefik/v2, github.com/traefik/traefik and github.com/traefik/traefik/v3. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/traefik/traefik/v2 Go | From 2.11.0 | 2.11.57 |
github.com/traefik/traefik/v2 Go | From 2.11.0 | 2.11.57 |
github.com/traefik/traefik/v2 Go | From 2.11.0 | 2.11.57 |
github.com/traefik/traefik Go | All versions | None |
github.com/traefik/traefik/v3 Go | From 3.0.0 | 3.7.13 |
github.com/traefik/traefik/v3 Go | From 3.0.0 | 3.7.13 |
1 more packages
github.com/traefik/traefik/v3 Go | From 3.0.0 | 3.7.13 |
Products include Traefik Traefik.
How do I fix CVE-2026-88007?
Upgrade github.com/traefik/traefik/v2 to 2.11.57 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-88007 being exploited?
There is no known exploitation of CVE-2026-88007 in the wild and no public exploit code.
Other vulnerabilities in Traefik Traefik
- CVE-2024-45410 HTTP client can remove the X-Forwarded headers in Traefik
- CVE-2026-88877 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect
- CVE-2026-85595 Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth
- CVE-2026-88009 Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging
- CVE-2025-32431 Traefik has a possible vulnerability with the path matchers
Sources
Also known as ECHO-22a3-b491-e65f, GHSA-qqjf-53cj-pwvv, GO-2026-6466, MINI-hphg-p675-wx3f, MINI-m2m3-mg8r-647g, MINI-x878-xwv5-8x62.