Ubuntu 24.04 LTS and Earlier OpenSSH Access Control Issue

ubuntu

April 24, 2025

OpenSSH could allow unintended access to network services.

Summary

OpenSSH could allow unintended access to network services.

Software Description:

- openssh: secure shell (SSH) for secure access to remote machines

Details:

It was discovered that OpenSSH incorrectly handled the DisableForwarding

directive. The directive would fail to disable X11 and agent forwarding,

contrary to documentation and expectations.

Topics Covered

security advisory access control Ubuntu OpenSSH network access X11 forwarding

Update Instructions

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

Ubuntu 25.04
   openssh-client                  1:9.9p1-3ubuntu3.1
   openssh-server                  1:9.9p1-3ubuntu3.1

Ubuntu 24.10
   openssh-client                  1:9.7p1-7ubuntu4.3
   openssh-server                  1:9.7p1-7ubuntu4.3

Ubuntu 24.04 LTS
   openssh-client                  1:9.6p1-3ubuntu13.11
   openssh-server                  1:9.6p1-3ubuntu13.11

Ubuntu 22.04 LTS
   openssh-client                  1:8.9p1-3ubuntu0.13
   openssh-server                  1:8.9p1-3ubuntu0.13

Ubuntu 20.04 LTS
   openssh-client                  1:8.2p1-4ubuntu0.13
   openssh-server                  1:8.2p1-4ubuntu0.13

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