Marmite through 0.4.2 Path Traversal via Development Server

Marmite through 0.4.2 contains a path traversal vulnerability in the development server started by --serve that allows unauthenticated attackers to read arbitrary files. The handle_request function in src/server.rs fails to reject .. segments after percent-decoding and joining the request path to the output folder, enabling attackers to request encoded traversal sequences to access files readable by the marmite process.