CVE-2026-88012

## Summary There is a medium severity vulnerability in Traefik's HTTP/3 entry points: the `respondingTimeouts` settings were not applied to the HTTP/3 request path. `readTimeout` in particular is on by default at 60s and is documented as bounding the time to read the entire request including its body, but it is enforced as a deadline on the TCP connection, which cannot reach a QUIC stream, and Traefik's HTTP/3 server was constructed with no timeout of any kind. An unauthenticated client that trickles a request body therefore holds a request open for as long as it chooses, and with it one upstream connection per request, at negligible cost to itself. Backends with bounded connection pools are the practical pressure point. The HTTP/3 path lost these timeouts in v2.8.2, when a quic-go API change removed the embedded `http.Server` that had carried them; every release from v2.8.2 onward is affected, and releases before v2.8.2 are not. Traefik v2.8.2 through v2.10.x and v3.0 through v3.6 are affected and are no longer maintained: they will not receive a patch on their own line, and the remedy for their users is to upgrade to v2.11.56 or v3.7.12. ## Patches - https://github.com/traefik/traefik/releases/tag/v2.11.56 - https://github.com/traefik/traefik/releases/tag/v3.7.12 ## For more information If you have any questions or comments about this advisory, please [open an issue](https://github.com/traefik/traefik/issues). <details> <summary>Original Description</summary> ## Summary `entryPoints.<name>.transport.respondingTimeouts.readTimeout` is documented as: > "Set the timeouts for incoming requests to the Traefik instance. This is the maximum > duration for reading the entire request, **including the body**." — **Default: 60s** It is **on by default** and it works over HTTP/1.1 and HTTP/2. It has **no effect on HTTP/3**. The consequence is not that a hardening option was left unset. It is that every Traefik deployment with `http3` enabled carries a 60-second bo