Ubuntu 20.04 LTS: USN-4656-1 Critical: X.Org X Server Privilege Escalation

ubuntu

December 1, 2020

Several security issues were fixed in X.Org X Server.

Summary

Several security issues were fixed in X.Org X Server.

Software Description:

- xorg-server: X.Org X11 server

- xorg-server-hwe-18.04: X.Org X11 server

- xorg-server-hwe-16.04: X.Org X11 server

Details:

Jan-Niklas Sohn discovered that the X.Org X Server XKB extension

incorrectly handled certain inputs. A local attacker could possibly use

this issue to escalate privileges.

Topics Covered

security advisory critical privilege escalation ubuntu x.org

Update Instructions

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

Ubuntu 20.10:
  xserver-xorg-core               2:1.20.9-2ubuntu1.1

Ubuntu 20.04 LTS:
  xserver-xorg-core               2:1.20.8-2ubuntu2.6

Ubuntu 18.04 LTS:
  xserver-xorg-core               2:1.19.6-1ubuntu4.8
  xserver-xorg-core-hwe-18.04     2:1.20.8-2ubuntu2.2~18.04.4

Ubuntu 16.04 LTS:
  xserver-xorg-core               2:1.18.4-0ubuntu0.11
  xserver-xorg-core-hwe-16.04     2:1.19.6-1ubuntu4.1~16.04.5

After a standard system update you need to reboot your computer to make all
the necessary changes.