ronf AsyncSSH up to 2.24.0 SFTP Client asyncssh/sftp.py SFTPClient._copy path traversal

Summaryinfo

A vulnerability, which was classified as problematic, has been found in ronf AsyncSSH up to 2.24.0. This affects the function SFTPClient._copy of the file asyncssh/sftp.py of the component SFTP Client. Performing a manipulation results in path traversal. This vulnerability was named CVE-2026-77473. The attack may be initiated remotely. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in ronf AsyncSSH up to 2.24.0. This affects the function SFTPClient._copy of the file asyncssh/sftp.py of the component SFTP Client. The manipulation with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. This is going to have an impact on integrity. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-77473 since 08/20/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1006 for this issue.

Upgrading to version 2.24.1 eliminates this vulnerability.

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Productinfo

Vendor

• ronf

Name

• AsyncSSH

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24.0

Website

• Product: https://github.com/ronf/asyncssh/

CPE 2.3info

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CPE 2.2info

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