Halloy has a file transfer path traveral vulnerability

Halloy is an IRC application written in Rust. Prior to commit 0f77b2cfc5f822517a256ea5a4b94bad8bfe38b6, the DCC receive flow did not sanitize filenames from incoming DCC SEND requests. A remote IRC user could send a filename with path traversal sequences like ../../.ssh/authorized_keys and the file would be written outside the user's configured save_directory. With auto-accept enabled this required zero interaction from the victim. Starting with commit 0f77b2cfc5f822517a256ea5a4b94bad8bfe38b6, all identified code paths sanitize filenames through a shared sanitize_filename function.