==========================================================================
Ubuntu Security Notice USN-7108-1
November 18, 2024

python-asyncssh vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS

Summary:

Several issues were fixed in AsyncSSH.

Software Description:
- python-asyncssh: asyncio-based client and server implementation of SSHv2 
protocol

Details:

Fabian Bäumer, Marcus Brinkmann, and Jörg Schwenk discovered that AsyncSSH
did not properly handle the extension info message. An attacker able to
intercept communications could possibly use this issue to downgrade
the algorithm used for client authentication. (CVE-2023-46445)

Fabian Bäumer, Marcus Brinkmann, and Jörg Schwenk discovered that AsyncSSH
did not properly handle the user authentication request message. An
attacker could possibly use this issue to control the remote end of an SSH
client session via packet injection/removal and shell emulation.
(CVE-2023-46446)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 24.04 LTS
   python3-asyncssh                2.10.1-2ubuntu0.1+esm1
                                   Available with Ubuntu Pro

Ubuntu 22.04 LTS
   python3-asyncssh                2.5.0-1ubuntu0.1

Ubuntu 20.04 LTS
   python3-asyncssh                1.12.2-1ubuntu0.2

In general, a standard system update will make all the necessary changes.

References:
   https://ubuntu.com/security/notices/USN-7108-1
   CVE-2023-46445, CVE-2023-46446

Package Information:
https://launchpad.net/ubuntu/+source/python-asyncssh/2.5.0-1ubuntu0.1
https://launchpad.net/ubuntu/+source/python-asyncssh/1.12.2-1ubuntu0.2