CVE-2026-54591

Name	CVE-2026-54591
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. Prior to 2.23.1, a malicious SSH server can write arbitrary files on the asyncssh SCP client's filesystem by sending filenames containing ../ traversal sequences because _parse_cd_args in scp.py returns server-provided names verbatim and _recv_files joins them to the destination path without enforcing the target directory boundary. This issue is fixed in version 2.23.1.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1141818

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
python-asyncssh (PTS)	bullseye	2.5.0-0.1	vulnerable
	bullseye (security)	2.5.0-0.1+deb11u1	vulnerable
	bookworm	2.10.1-2+deb12u2	vulnerable
	bookworm (security)	2.10.1-2+deb12u1	vulnerable
	trixie	2.20.0-1	vulnerable
	forky, sid	2.23.0-1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
python-asyncssh	source	(unstable)	(unfixed)			1141818

Notes

https://github.com/ronf/asyncssh/security/advisories/GHSA-2wxc-x7rj-hg8f
Fixed by: https://github.com/ronf/asyncssh/commit/d730803b8e4e94c20c7580d90f94d1e05f9f58de (v2.23.1)