Traefik is an open source HTTP reverse proxy and load balancer. When Traefik is configured to use the `HTTPChallenge` to generate and renew the Let's Encrypt TLS certificates, the delay authorized to solve the challenge (50 seconds) can be exploited by attackers to achieve a `slowloris attack`. This vulnerability has been patch in version 2.10.6 and 3.0.0-beta5. Users are advised to upgrade. Users unable to upgrade should replace the `HTTPChallenge` with the `TLSChallenge` or the `DNSChallenge`.
https://www.cloudflare.com/learning/ddos/ddos-attack-tools/slowloris
https://github.com/traefik/traefik/security/advisories/GHSA-8g85-whqh-cr2f
https://github.com/traefik/traefik/releases/tag/v3.0.0-beta5
https://github.com/traefik/traefik/releases/tag/v2.10.6
https://doc.traefik.io/traefik/https/acme/#tlschallenge