CVE-2026-54590: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in ronf asyncssh
AsyncSSH version 2.23.0 contains a path traversal vulnerability in the SSHServerConfig._set_tokens function. The vulnerability arises because the fix for a previous issue (CVE-2026-45309) is incomplete: it blocks certain characters before %u substitution in AuthorizedKeysFile but does not block leading ~ or ${ENV}, allowing expansion that can escape the intended authorized-keys directory. This issue is resolved in version 2.23.1.
AI Analysis
Technical Summary
CVE-2026-54590 is a path traversal vulnerability in the AsyncSSH Python package version 2.23.0. The vulnerability occurs in SSHServerConfig._set_tokens where an incomplete fix for a prior vulnerability fails to block leading ~ or environment variable expansions (${ENV}) in the AuthorizedKeysFile path. This allows the path to escape the restricted authorized-keys directory via expansion in _expand_val and Path(filename).expanduser(). The issue is fixed in version 2.23.1.
Potential Impact
The vulnerability allows an attacker to bypass directory restrictions on the AuthorizedKeysFile path, potentially enabling unauthorized modification or use of SSH authorized keys. The CVSS score is 5.9 (medium severity) with no confidentiality or availability impact but with high integrity impact. No known exploits in the wild have been reported.
Mitigation Recommendations
Upgrade AsyncSSH to version 2.23.1 or later, where this path traversal vulnerability is fixed. No other mitigations are indicated by the vendor advisory. Patch status is confirmed by the fix in 2.23.1.
CVE-2026-54590: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in ronf asyncssh
Description
AsyncSSH version 2.23.0 contains a path traversal vulnerability in the SSHServerConfig._set_tokens function. The vulnerability arises because the fix for a previous issue (CVE-2026-45309) is incomplete: it blocks certain characters before %u substitution in AuthorizedKeysFile but does not block leading ~ or ${ENV}, allowing expansion that can escape the intended authorized-keys directory. This issue is resolved in version 2.23.1.
CVSS v3.1
Score 5.9medium
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-54590 is a path traversal vulnerability in the AsyncSSH Python package version 2.23.0. The vulnerability occurs in SSHServerConfig._set_tokens where an incomplete fix for a prior vulnerability fails to block leading ~ or environment variable expansions (${ENV}) in the AuthorizedKeysFile path. This allows the path to escape the restricted authorized-keys directory via expansion in _expand_val and Path(filename).expanduser(). The issue is fixed in version 2.23.1.
Potential Impact
The vulnerability allows an attacker to bypass directory restrictions on the AuthorizedKeysFile path, potentially enabling unauthorized modification or use of SSH authorized keys. The CVSS score is 5.9 (medium severity) with no confidentiality or availability impact but with high integrity impact. No known exploits in the wild have been reported.
Mitigation Recommendations
Upgrade AsyncSSH to version 2.23.1 or later, where this path traversal vulnerability is fixed. No other mitigations are indicated by the vendor advisory. Patch status is confirmed by the fix in 2.23.1.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-15T19:45:23.538Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4eb690c9d9e3dbe3b68725
Added to database: 07/08/2026, 20:44:00 UTC
Last enriched: 07/08/2026, 20:59:24 UTC
Last updated: 07/09/2026, 01:44:28 UTC
Views: 4
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