Vulnerability · Published Jul 8, 2026 · Assigned by GitHub_M
CVE-2026-54591AsyncSSH: SCP Path Traversal to Arbitrary File Write
High 8.1
In plain English
A high-severity path traversal in asyncssh from ronf. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-asyncssh | no fix listed | DEBIAN-CVE-2026-54591 |
| Debian:13 | python-asyncssh | no fix listed | DEBIAN-CVE-2026-54591 |
| Debian:14 | python-asyncssh | 2.24.0-1 | DEBIAN-CVE-2026-54591 |
| PyPI | asyncssh | 2.23.1 | PYSEC-2026-3808 |
| PyPI | asyncssh | 2.23.1 | GHSA-2wxc-x7rj-hg8f |
| Ubuntu:25.10 | python-asyncssh | no fix listed | UBUNTU-CVE-2026-54591 |
| Ubuntu:26.04:LTS | python-asyncssh | no fix listed | UBUNTU-CVE-2026-54591 |
| Ubuntu:26.10 | python-asyncssh | no fix listed | UBUNTU-CVE-2026-54591 |
Affected products (as reported)
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
References
- https://github.com/ronf/asyncssh/security/advisories/GHSA-2wxc-x7rj-hg8f x_refsource_CONFIRM
- https://github.com/ronf/asyncssh/commit/d730803b8e4e94c20c7580d90f94d1e05f9f58de x_refsource_MISC
- https://github.com/ronf/asyncssh/releases/tag/v2.23.1 x_refsource_MISC