AsyncSSH: SFTP Recursive Copy Path Traversal via Unsanitized Server-Supplied Filenames
- Exploited
- No known exploitation
- Fix
- Fixed in 2.24.1
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 2.24.1.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 14/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
AsyncSSH, a Python library for SSHv2 client and server use, has a path traversal flaw in its recursive SFTP copy routine used by get(), mget(), and copy(), where a malicious or compromised SFTP server can return crafted filenames that make the client write attacker-chosen content to arbitrary locations the client process can write to. The bug can be reached remotely over the network without logging in, but it requires the victim client to take an action such as performing a recursive copy from that server.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original 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 2.24.1, 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.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure7/25Reachable over the network without a login · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity6.5/10CVSS 6.5
- No patch0/5No signal
What would change the score
- Would score about 69 if added to CISA KEV
- Would score about 64 if CISA's SSVC rates exploitation active
- Would score about 29 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 2.24.1.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- ronf asyncssh
fixed in 2.24.1
Evidence 3
- Advisory
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-77473
Is CVE-2026-77473 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-77473?
asyncssh: before 2.24.1.Source: cve.now feed data
How do I fix CVE-2026-77473?
Upgrade to a fixed version: 2.24.1.Source: cve.now feed data