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 contains an incomplete fix for CVE-2026-45309 in SSHServerConfig.settokens that blocks /, , and .. before %u substitution in...

CVE-2026-54590

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.settokens that blocks /, , and .. before %u substitution in...

PT-2026-56577

Name of the Vulnerable Software and Affected Versions AsyncSSH version 2.23.0 Description An incomplete fix in the SSHServerConfig. set tokens function fails to block leading or $ENV characters before %u substitution in the AuthorizedKeysFile. This allows subsequent expansion in expand val and...