Traefik is an open source HTTP reverse proxy and load balancer. The traefik docker container uses 100% CPU when it serves as its own backend, which is an automatically generated route resulting from the Docker integration in the default configuration. This issue has been addressed in versions 2.10.6 and 3.0.0-beta5. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Affected: Go: github.com/traefik/traefik/v2, Go: github.com/traefik/traefik/v3

### Summary

The traefik docker container uses 100% CPU when it serves as its own backend, which is an automatically generated route resulting from the Docker integration in the default configuration.

### Details

While attempting to set up Traefik to handle traffic for Docker containers, I observed in the webUI a rule with the following information:

`Host(traefik-service) | webwebsecure | traefik-service@docker | traefik-service`

I assumed that this is something internal; however, I wondered why it would have a host rule on the web entrypoint configured.

So I have send a request with that hostname with `curl -v --resolve "traefik-service:80:xxx.xxx.xxx.xxx" http://traefik-service`. That made my whole server unresponsive.

I assume the name comes from a docker container with that name, traefik itself: ``` localhost ~ # docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d1414e74aec7 traefik:v2.10 "/entrypoint.sh trae…" 4 minutes ago Up 4 minutes 0.0.0.0:80->80/tcp, :::80->80/tcp, 0.0.0.0:443->443/tcp, :::443->443/tcp, 127.0.0.1:8080->8080/tcp traefik.service ```

### PoC

1. Start traefik with `docker run --rm -v /var/run/docker.sock:/var/run/docker.sock -p 80:80 --name foo -p 8080:8080 traefik:v2.10 --api.insecure=true --p…

traefik-2.10.7-1.1 on GA media