CVE-2026-54590 — AsyncSSH AuthorizedKeysFile username substitution bypass through ~ and environment expansion
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 contain…
Published: 2026-07-08 · CVSS: 5.9 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7