Salvo is a Rust web framework. Versions 0.39.0 through 0.89.2 have a Path Traversal and Access Control Bypass vulnerability in the salvo-proxy component. The vulnerability allows an unauthenticated external attacker to bypass proxy routing constraints and access unintended backend paths (e.g., protected endpoints or administrative dashboards). This issue stems from the encode_url_path function, which fails to normalize "../" sequences and inadvertently forwards them verbatim to the upstream server by not re-encoding the "." character. Version 0.89.3 contains a patch.