AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Version 2.23.0 contains an incomplete fix for CVE-2026-45309 in SSHServerConfig._set_tokens that blocks /, , and .. before %u substitution in AuthorizedKeysFile but does not block a leading ~ or ${ENV}, allowing later expansion in _expand_val and Path(filename).expanduser() to escape the intended authorized-keys directory. This issue is fixed in version 2.23.1.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2
    protocol on top of the Python asyncio framework. Version 2.23.0 contains an incomplete fix for
    CVE-2026-45309 in SSHServerConfig._set_tokens that blocks /, , and .. before %u substitution in
    AuthorizedKeysFile but does not block a leading ~ or ${ENV}, allowing later expansion in _expand_val and
    Path(filename).expanduser() to escape the intended authorized-keys directory. This issue is fixed in
    version 2.23.1. (CVE-2026-54590)

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-1f248487e4 advisory.

    update to version 2.24.0     Fix CVE-2026-54590: Unauthorized file modification via authorized-keys directory escape     Fix CVE-2026-54591: Arbitrary file write via path traversal in SCP client

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-574496d9ae advisory.

    import asyncssh 2.23.1     Fix CVE-2026-54590: Unauthorized file modification via authorized-keys directory escape     Fix CVE-2026-54591: Arbitrary file write via path traversal in SCP client

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2     protocol on top of the Python asyncio framework. Version 2.23.0 contains an incomplete fix for     CVE-2026-45309 in SSHServerConfig._set_tokens that blocks /, , and .. before %u substitution in     AuthorizedKeysFile but does not block a leading ~ or ${ENV}, allowing later expansion in _expand_val and     Path(filename).expanduser() to escape the intended authorized-keys directory. This issue is fixed in     version 2.23.1. (CVE-2026-54590)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
463473	Echo: asyncssh: security update to 2.23.1	Tenable Cloud Security	Echo Local Security Checks	Local	medium
463473	Echo: asyncssh: security update to 2.23.1	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	medium
446359	SCA: security update for asyncssh (GHSA-qr67-gv47-xwwh)	Tenable Cloud Security	SCA Checks	Local	medium
446359	SCA: security update for asyncssh (GHSA-qr67-gv47-xwwh)	Tenable Self-Hosted Container Security	SCA Checks	Local	medium
327896	Fedora 44 : python-asyncssh (2026-1f248487e4)	Nessus	Fedora Local Security Checks	Local	high
327895	Fedora 43 : python-asyncssh (2026-574496d9ae)	Nessus	Fedora Local Security Checks	Local	high
326086	Linux Distros Unpatched Vulnerability : CVE-2026-54590	Nessus	Misc.	Local	medium

Detections

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CVE-2026-54590

medium

Tenable Plugins

medium

medium

medium

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high

high

medium