🛡️ CVE-2026-45309 on Ubuntu — python-asyncssh

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

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.

Distribution advisory

This page covers CVE-2026-45309 as tracked by Ubuntu, for the package python-asyncssh. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity high, availability none.

Weakness class

UBUNTU-CVE-2026-45309 is classified as CWE-22: Path Traversal. A file path built from user input is not confined to the intended directory, letting an attacker reach files elsewhere on the filesystem.

Affected software

UBUNTU-CVE-2026-45309 is recorded against 1 package.

python-asyncssh

Timeline and source

Published on 17 July 2026 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
github.com (Report)

Details

Severity Unknown

CVSS Score N/A

CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2026-07-17

Updated 2026-08-11

Modified 2026-08-04

Fix URL N/A

Affected Packages

Software	From version	Fixed in
python-asyncssh	—	—

References

REPORT https://ubuntu.com/security/CVE-2026-45309

REPORT https://www.cve.org/CVERecord?id=CVE-2026-45309

REPORT https://github.com/advisories/GHSA-g794-3fmp-753h

🔗 NVD 🔗 Mitre

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