CVE-2026-71324
Last modified
CVE-2026-71324 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.53, 3.6.24, and 3.7.9, Traefik's default HTTP reverse proxy forwards a plain HTTP/2 or HTTP/3 CONNECT request and its body to an HTTP/1.1 upstream through a shared net/http.Transport. EPSS estimates a 0.55% chance of exploitation in the next 30 days.
Description
Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.53, 3.6.24, and 3.7.9, Traefik's default HTTP reverse proxy forwards a plain HTTP/2 or HTTP/3 CONNECT request and its body to an HTTP/1.1 upstream through a shared net/http.Transport. When the upstream answers the CONNECT with a keep-alive non-2xx response and does not drain the body, Traefik returns the desynchronized backend socket to its shared pool and reuses it for other clients. An unauthenticated attacker can use this behavior to make a different client read the attacker's smuggled response, which can include authenticated or private content from another request. The ForwardAuth middleware with forwardBody true and preserveRequestMethod true can re-issue a CONNECT with the buffered body attached, exposing the auth-client pool to the same desynchronization. This issue is fixed in 2.11.53, 3.6.24, and 3.7.9.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Traefik | Traefik | < 2.11.53 |
| Traefik | Traefik | >= 3.0.0, < 3.6.24 |
| Traefik | Traefik | >= 3.7.0, < 3.7.9 |
References
- https://github.com/traefik/traefik/pull/13542Issue Tracking, Patch
- https://github.com/traefik/traefik/pull/13543Issue Tracking, Patch
- https://github.com/traefik/traefik/pull/13556Issue Tracking, Patch
- https://github.com/traefik/traefik/security/advisories/GHSA-3ccp-42pg-hgv6Patch, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
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