UBUNTU-CVE-2026-54590
AsyncSSH versions up to 2.23.0 contain an incomplete fix for a vulnerability in SSHServerConfig._set_tokens that allows expansion of leading ~ or ${ENV} in authorized keys file paths, potentially escaping the intended directory. This issue is fixed in version 2.23.1.
AI Analysis
Technical Summary
AsyncSSH is a Python package implementing SSHv2 asynchronously. Version 2.23.0 attempted to fix CVE-2026-45309 by blocking certain tokens in AuthorizedKeysFile paths but failed to block leading ~ or ${ENV} expansions. This allows path expansion via _expand_val and Path(filename).expanduser(), potentially escaping the authorized-keys directory. The vulnerability is addressed in version 2.23.1.
Potential Impact
The vulnerability allows an attacker to bypass directory restrictions on authorized keys files by exploiting unblocked expansions (~ or ${ENV}), potentially leading to unauthorized modification or use of SSH authorized keys. The CVSS vector indicates no confidentiality or availability impact but a high impact on integrity, requiring network attack with high attack complexity and no privileges or user interaction.
Mitigation Recommendations
Upgrade AsyncSSH to version 2.23.1 or later, where this issue is fixed. No other mitigation is indicated.
UBUNTU-CVE-2026-54590
Description
AsyncSSH versions up to 2.23.0 contain an incomplete fix for a vulnerability in SSHServerConfig._set_tokens that allows expansion of leading ~ or ${ENV} in authorized keys file paths, potentially escaping the intended directory. This issue is fixed in version 2.23.1.
CVSS v3.1
Score 5.9medium
Affected software
pkg:deb/ubuntu/[email protected]?arch=source&distro=xenialpkg:deb/ubuntu/[email protected]~esm2?arch=source&distro=esm-apps/bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]+esm1?arch=source&distro=esm-apps/jammypkg:deb/ubuntu/[email protected]+esm1?arch=source&distro=esm-apps/noblepkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
AsyncSSH is a Python package implementing SSHv2 asynchronously. Version 2.23.0 attempted to fix CVE-2026-45309 by blocking certain tokens in AuthorizedKeysFile paths but failed to block leading ~ or ${ENV} expansions. This allows path expansion via _expand_val and Path(filename).expanduser(), potentially escaping the authorized-keys directory. The vulnerability is addressed in version 2.23.1.
Potential Impact
The vulnerability allows an attacker to bypass directory restrictions on authorized keys files by exploiting unblocked expansions (~ or ${ENV}), potentially leading to unauthorized modification or use of SSH authorized keys. The CVSS vector indicates no confidentiality or availability impact but a high impact on integrity, requiring network attack with high attack complexity and no privileges or user interaction.
Mitigation Recommendations
Upgrade AsyncSSH to version 2.23.1 or later, where this issue is fixed. No other mitigation is indicated.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-54590
- Osv Schema Version
- 1.7.0
- Aliases
- []
- Ecosystems
- ["Ubuntu:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:Pro:22.04:LTS","Ubuntu:Pro:24.04:LTS","Ubuntu:25.10","Ubuntu:26.04:LTS"]
- Database Specific Severity
- null
- Cvss Version
- 3.1
Threat ID: 6a58b47868715ace43d98317
Added to database: 07/16/2026, 10:37:44 UTC
Last enriched: 07/16/2026, 11:53:43 UTC
Last updated: 07/31/2026, 19:24:50 UTC
Views: 3
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