Review reviewHigh

CVE-2026-45309

ronf asyncssh

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...

CVSS: 8.2
EPSS: 0.44%
CISA KEV: Not listed
Published: 2026.07.18

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.44%

Technical severityCVSS 8.2

Vulnerability overview

Affected product and versions

Product: ronf asyncssh
Affected versions: >= < 2.23.0, < 2.23.0
Fixed versions: 2.23.0

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that ronf asyncssh and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE: CWE-22