AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Prior to 2.23.1, a malicious SSH server can write arbitrary files on the asyncssh SCP client's filesystem by sending filenames containing ../ traversal sequences because parsecd_args in scp.py returns server-provided names verbatim and recvfiles joins them to the destination path without enforcing the target directory boundary. This issue is fixed in version 2.23.1.