5.9 MEDIUM
- CVSS version (CVSS): 3.1
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): High (H)
- Privileges Required (PR): None (N)
- User Interaction (UI): None (N)
- Scope (S): Unchanged (U)
- Confidentiality (C): None (N)
- Integrity (I): High (H)
- Availability (A): None (N)
- Modified Attack Vector (MAV): Network (N)
- Modified Attack Complexity (MAC): High (H)
- Modified Privileges Required (MPR): None (N)
- Modified User Interaction (MUI): None (N)
- Modified Confidentiality (MC): None (N)
- Modified Scope (MS): Unchanged (U)
- Modified Integrity (MI): High (H)
- Modified Availability (MA): None (N)
Activity log
- Created suggestion
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._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.
References
-
https://github.com/ronf/asyncssh/security/advisories/GHSA-qr67-gv47-xwwh x_refsource_CONFIRM
-
https://github.com/ronf/asyncssh/releases/tag/v2.23.1 x_refsource_MISC
Affected products
- ==< 2.23.1
Matching in nixpkgs
pkgs.python313Packages.asyncssh
Asynchronous SSHv2 Python client and server library