CVE-2026-45309: AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 prot

Q: How do I fix CVE-2026-45309?

asyncssh: upgrade to 2.23.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-45309 being exploited?

CVE-2026-45309 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-45309 affect?

CVE-2026-45309 affects asyncssh. Severity is high (CVSS 7.5). 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

Q: How urgent is CVE-2026-45309?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-45309 is a high-severity flaw (CVSS 7.5) affecting asyncssh. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 AuthorizedK

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-22
Published	2026-07-17
Last modified	2026-10-24

Publisher (CNA): GitHub, Inc. · Vendor: asyncssh project

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-17 19:17 UTCPublished CVE record published
2026-10-24 20:10 UTCUpdated Record last modified

asyncssh project asyncssh UPGRADE

Affected: < 2.23.0

Fixed in: 2.23.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy asyncssh || rpm -q asyncssh || asyncssh --version

2. UPGRADE to 2.23.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade asyncssh

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade asyncssh

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-45309?

asyncssh: upgrade to 2.23.0. Exact commands for each OS are on this page.

Is CVE-2026-45309 being exploited?

CVE-2026-45309 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-45309 affect?

CVE-2026-45309 affects asyncssh. Severity is high (CVSS 7.5). 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

How urgent is CVE-2026-45309?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

OpenSSH vulnerabilities · Python vulnerabilities

References

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