Description
AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Version 2.23.0 contains an incomplete fix for CVE-2026-45309 in SSHServerConfig._set_tokens that blocks /, , and .. before %u substitution in AuthorizedKeysFile but does not block a leading ~ or ${ENV}, allowing later expansion in _expand_val and Path(filename).expanduser() to escape the intended authorized-keys directory. This issue is fixed in version 2.23.1.
Problem types
CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-639: Authorization Bypass Through User-Controlled Key
Product status
References
github.com/...yncssh/security/advisories/GHSA-qr67-gv47-xwwh
github.com/...ommit/3d515ba9ba0cd9990d248bdf62bcf05d51261a88
github.com/ronf/asyncssh/releases/tag/v2.23.1