# CVE-2026-77473: AsyncSSH: SFTP Recursive Copy Path Traversal via Unsanitized Server-Supplied Filenames

Status: published. Published: 2026-11-09. Updated: 2026-11-09.

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 2.24.1, recursive remote-to-local SFTP copies in SFTPClient._copy() in asyncssh/sftp.py, reached through get(), mget(), and copy(), trust filenames returned by a remote server's directory enumeration. A malicious or compromised SFTP server can return an absolute filename or a filename containing path separators and parent-directory traversal, causing destination path construction to escape the requested local directory and write attacker-selected content to locations writable by the client process. This issue is fixed in version 2.24.1.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- ronf / asyncssh: < 2.24.1 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-22

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/ronf/asyncssh/security/advisories/GHSA-q8m6-9rfx-39rf (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/ronf/asyncssh/commit/eaf7fd3b058ccb36b51ed932158d36cf304aa7c3 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/ronf/asyncssh/releases/tag/v2.24.1 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-77473; retrieved 2026-11-09; source updated 2026-11-09

Revision: 24e3105f17dea01467189e6da81f69a4d4bf8bae6111252eac28e138726b3d13

Canonical: https://y2.dev/cve/CVE-2026-77473

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