actix-files before 0.6.10 Information Disclosure via Files

The actix-files crate (actix_files) before version 0.6.10 contains an information exposure vulnerability. When a non-existing folder is passed as the serve_from argument to Files::new(), the mount path defaults to an empty path; the service then joins the request path with this empty path and canonicalizes it, causing Rust to resolve it as a relative path. As a result, an attacker can request paths that resolve relative to the application's working directory and access unintended files.