CVE-2026-54590: AsyncSSH AuthorizedKeysFile username substitution bypass through ~ and environment expansion
ronf · asyncssh
Affected: ronf asyncssh · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 27% of scored CVEs
DescriptionCVE.org
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.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- ronf · asyncssh< 2.23.1
On the Atlas
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CoverageNo articles yet
No CyberSIXT article names CVE-2026-54590 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.