Path traversal in ronf asyncssh
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- Partial Red Hat: 3 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat.
Summary
AsyncSSH 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 2.23.0, AsyncSSH expands the OpenSSH-compatible AuthorizedKeysFile %u token in asyncssh/config.py, asyncssh/connection.py, asyncssh/auth_keys.py, and asyncssh/misc.py with the raw SSH username during pre-authentication server config reload, allowing a server configured with AuthorizedKeysFile authorized_keys/%u to read an authorized-keys file outside the intended directory when the SSH username contains /, \, or .. path traversal segments and authenticate with an attacker-selected key file. This issue is fixed in version 2.23.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| ronf | asyncssh | before 2.23.0 | 2.23.0 | Patch available | CNA |
| — | asyncssh (PyPI) | 2.22.0 to before 2.23.0 | 2.23.0 | Patch available | GHSA-g794-3fmp-753h |
- asyncssh Vendorronf Affected before 2.23.0 Fixed in 2.23.0 Patch available CNA
- asyncssh (PyPI) Vendor— Affected 2.22.0 to before 2.23.0 Fixed in 2.23.0 Patch available GHSA-g794-3fmp-753h
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:asyncssh_project:asyncssh:*:*:*:*:*:*:*:* | before 2.23.0 | Vulnerable | Asyncssh Project |
- cpe:2.3:a:asyncssh_project:asyncssh:*:*:*:*:*:*:*:* Versions before 2.23.0 Vulnerable ·Asyncssh Project
Remediation
- Fix · CNA asyncssh (ronf) Fixed in 2.23.0
- Fix · GHSA-g794-3fmp-753h asyncssh (PyPI) Fixed in 2.23.0 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Ceph Storage 7 | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 8 | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 9 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-45309
- 2026-10-03 Alias added: GHSA-g794-3fmp-753h
References
More ronf vulnerabilities
- TI-2026-39424 AsyncSSH AuthorizedKeysFile username substitution bypass through ~ and environment expansion CVSS 3.1MEDIUM 5.9
- TI-2026-39425 AsyncSSH: SCP Path Traversal to Arbitrary File Write CVSS 3.1HIGH 8.1
- TI-2026-44984 AsyncSSH: asyncio event-loop freeze via SSH maximum packet size = 0 in SSH_MSG_CHANNEL_OPEN / OPEN_CONFIRMATION CVSS 3.1MEDIUM 6.5
Sources
- CVE-2026-45309 · CVE Program
- CVE-2026-45309 · NVD
- FIRST EPSS
- GHSA-g794-3fmp-753h · GitHub Advisory Database · CC BY 4.0
- CVE-2026-45309 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences