Hello @GoingOffRoading ,
Indeed Traefik is not affected at all by the vulnerability, but being a common proxy solution for people using affected backends there are mentions and questions here and there.
The main question is how can you secure your affected backend that is exposed by Traefik until you can fix its code permanently.
We have two options here, the first being a simple addition of a HeadersRegexp matching on the router to filter out the user-agent header. That approach does not cover all use cases but it's quick and easy enough for the most common ones.
The second and more complete approach would be to write a custom plugin.
You can find an example for the first approach here, and we are working to create an example plugin soon.