CVE-2026-54591
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAsyncSSH 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceAsyncSSH before 2.23.1 contains a path traversal vulnerability in its SCP client implementation. The _parse_cd_args function in scp.py returns server-supplied filenames without sanitization, and _recv_files subsequently joins these to the destination path without validating directory boundaries, allowing a malicious server to write files outside the intended target directory using ../ sequences.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Determine installed AsyncSSH versionRun 'pip show asyncssh' or 'python -c "import asyncssh; print(asyncssh.__version__)"'Affected if Version is lower than 2.23.1
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Verify SCP client usage in codeSearch project code for imports of asyncssh.scp or usage of SCPClient class, e.g., grep for 'from asyncssh' and 'SCPClient' or 'scp'Affected if Code uses AsyncSSH's SCP client to receive files from remote servers
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Check if SCP receives files from external/untrusted serversReview application logic to see if SCP client connects to remote servers that are not fully trusted or controlled by the same entityAffected if Application uses AsyncSSH SCP client to receive files from servers that are not fully trusted or verified
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Inspect destination path handlingReview code that handles the destination path argument passed to SCPClient or scp receive operationsAffected if Destination path is not validated to be within an expected directory boundary before file transfer
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Test for path traversal in SCP operations (if environment permits)Set up a controlled test with a mock malicious server sending filenames containing ../ sequences and observe if files are written outside the intended directoryAffected if Files with ../ sequences in filenames are written outside the specified destination directory
User is affected if AsyncSSH version is below 2.23.1 AND the application uses AsyncSSH's SCP client to receive files from servers (especially untrusted or external ones) without additional path validation safeguards.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade AsyncSSH to version 2.23.1 or later to obtain the path traversal fix in the _parse_cd_args function.
asyncssh version 2.23.1
- Check current asyncssh version installed: pip show asyncssh or pip list | grep asyncssh
- Upgrade asyncssh to version 2.23.1 or later: pip install --upgrade asyncssh>=2.23.1
- Verify the upgrade was successful: pip show asyncssh (confirm version is 2.23.1 or higher)
- Test SCP functionality to ensure the upgrade does not break existing workflows
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-54591 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-54591 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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