# CVE-2026-88007

## Summary

- **CVE ID:** CVE-2026-88007
- **Severity:** CRITICAL
- **CVSS Score:** 9.1 (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)
- **CWE:** CWE-287, CWE-863
- **Published:** Sep 10, 2026
- **Last Modified:** Sep 10, 2026

## 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.

## Affected Products

- traefik — traefik (>= 2.11.0, < 2.11.57)
- traefik — traefik (>= 3.0.0, < 3.7.13)

## References

- [CNA](https://github.com/traefik/traefik/security/advisories/GHSA-qqjf-53cj-pwvv)
- [CNA](https://github.com/traefik/traefik/pull/13812)
- [CNA](https://github.com/traefik/traefik/commit/ff39c47d7459dec9cd8de63c1a4e7aa7315bdc1c)
- [CNA](https://github.com/traefik/traefik/releases/tag/v2.11.57)
- [CNA](https://github.com/traefik/traefik/releases/tag/v3.7.13)

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._