There exists a potential open redirect vulnerability in Traefik's handling of the
X-Forwarded-Prefix header. Active Exploitation of this issue is unlikely as it would require active header injection, however the Traefik team may want to address this issue nonetheless to prevent abuse in e.g. cache poisoning scenarios.
The Traefik API dashboard component doesn't validate that the value of the header
X-Forwarded-Prefix is a site relative path and will redirect to any header provided URI.
$ curl --header 'Host:docker.localhost' --header 'X-Forwarded-Prefix:https://foo.nl' 'http://localhost:8081' <a href="https://foo.nl/dashboard/">Found</a>.`
A successful exploitation of an open redirect can be used to entice victims to disclose sensitive information.
This issue was found by the GitHub Application Security Team and reported on behalf of the GHAS by the GitHub Security Lab Team.
You can contact the GHSL team at
firstname.lastname@example.org, please include
GHSL-2020-140 in any communication regarding this issue.