Perry before 0.5.1159 contains a path traversal vulnerability that allows a malicious build server to write arbitrary content to any location writable by the running process by supplying unsanitized path components in the artifact_name field of ArtifactReady WebSocket messages. Attackers controlling the server URL can deliver traversal payloads through the artifact_name or download_path fields, causing the client to overwrite sensitive files or expose arbitrary local files to an attacker-accessible location.