USN-4905-1: X.Org X Server vulnerability

Releases

• Ubuntu 20.10
• Ubuntu 20.04 LTS
• Ubuntu 18.04 ESM
• Ubuntu 16.04 ESM

Packages

• xorg-server - X.Org X11 server
• xorg-server-hwe-16.04 - X.Org X11 server
• xorg-server-hwe-18.04 - X.Org X11 server

Details

Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled
certain lengths of XInput extension ChangeFeedbackControl requests. An
attacker could use this issue to cause the server to crash, resulting in a
denial of service, or possibly execute arbitrary code.

Update instructions

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

Ubuntu 20.10

• xserver-xorg-core - 2:1.20.9-2ubuntu1.3

Ubuntu 20.04

• xserver-xorg-core - 2:1.20.9-2ubuntu1.2~20.04.2

Ubuntu 18.04

• xserver-xorg-core - 2:1.19.6-1ubuntu4.9
• xserver-xorg-core-hwe-18.04 - 2:1.20.8-2ubuntu2.2~18.04.5

Ubuntu 16.04

• xserver-xorg-core - 2:1.18.4-0ubuntu0.12
• xserver-xorg-core-hwe-16.04 - 2:1.19.6-1ubuntu4.1~16.04.6

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

References

• CVE-2021-3472

Related notices

• USN-4905-2: xserver-xorg-dev, xserver-common, xserver-xephyr, xdmx-tools, xnest, xorg-server-source, xserver-xorg-core-udeb, xserver-xorg-xmir, xdmx, xorg-server, xserver-xorg-core, xvfb