CVE-2026-45309

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 2.23.0, AsyncSSH expands the OpenSSH-compatible AuthorizedKeysFile %u token in asyncssh/config.py, asyncssh/connection.py,...

CVE-2026-45309 AsyncSSH `AuthorizedKeysFile %u` path traversal allows attacker-selected authorized keys to authenticate a traversal username

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 2.23.0, AsyncSSH expands the OpenSSH-compatible AuthorizedKeysFile %u token in asyncssh/config.py, asyncssh/connection.py,...

CVE-2026-45309

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 2.23.0, AsyncSSH expands the OpenSSH-compatible AuthorizedKeysFile %u token in asyncssh/config.py, asyncssh/connection.py,...

CVE-2026-54590

A flaw was found in AsyncSSH, a Python package for implementing the SSHv2 protocol. An incomplete fix for a previous vulnerability allowed an attacker to bypass security restrictions in the AuthorizedKeysFile processing. By using specific characters like or environment variables $ENV in the...

DEBIAN-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...

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...

Directory Traversal

Overview Affected versions of this package are vulnerable to Directory Traversal via the AuthorizedKeysFile %u token. An attacker can gain unauthorized SSH authentication by supplying a specially crafted username containing path traversal sequences, allowing the server to read an...

GHSA-G794-3FMP-753H AsyncSSH `AuthorizedKeysFile %u` path traversal allows attacker-selected authorized keys to authenticate a traversal username

Summary AsyncSSH 2.22.0 expands the OpenSSH-compatible AuthorizedKeysFile %u token with the raw SSH username during pre-authentication server config reload. A server configured with a documented per-user key pattern such as AuthorizedKeysFile authorizedkeys/%u can be made to read an authorized-ke...