A regression was fixed in X.Org X Server

==========================================================================
Ubuntu Security Notice USN-6587-3
January 30, 2024

xorg-server, xwayland regression
==========================================================================

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

- Ubuntu 23.10
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS

Summary:

A regression was fixed in X.Org X Server

Software Description:
- xorg-server: X.Org X11 server
- xwayland: X server for running X clients under Wayland

Details:

USN-6587-1 fixed vulnerabilities in X.Org X Server. The fix was incomplete
resulting in a possible regression. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

  Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled
  memory when processing the DeviceFocusEvent and ProcXIQueryPointer APIs. An
  attacker could possibly use this issue to cause the X Server to crash,
  obtain sensitive information, or execute arbitrary code. (CVE-2023-6816)
   Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled
  reattaching to a different master device. An attacker could use this issue
  to cause the X Server to crash, leading to a denial of service, or possibly
  execute arbitrary code. (CVE-2024-0229)
   Olivier Fourdan and Donn Seeley discovered that the X.Org X Server
  incorrectly labeled GLX PBuffers when used with SELinux. An attacker could
  use this issue to cause the X Server to crash, leading to a denial of
  service. (CVE-2024-0408)
   Olivier Fourdan discovered that the X.Org X Server incorrectly handled
  the curser code when used with SELinux. An attacker could use this issue to
  cause the X Server to crash, leading to a denial of service.
  (CVE-2024-0409)
   Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled
  memory when processing the XISendDeviceHierarchyEvent API. An attacker
  could possibly use this issue to cause the X Server to crash, or execute
  arbitrary code. (CVE-2024-21885)
   Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled
  devices being disabled. An attacker could possibly use this issue to cause
  the X Server to crash, or execute arbitrary code. (CVE-2024-21886)

Update instructions:

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

Ubuntu 23.10:
   xserver-xorg-core               2:21.1.7-3ubuntu2.7

Ubuntu 22.04 LTS:
   xserver-xorg-core               2:21.1.4-2ubuntu1.7~22.04.8
   xwayland                        2:22.1.1-1ubuntu0.11

Ubuntu 20.04 LTS:
   xserver-xorg-core               2:1.20.13-1ubuntu1~20.04.15
   xwayland                        2:1.20.13-1ubuntu1~20.04.15

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

References:
   https://ubuntu.com/security/notices/USN-6587-3
   https://ubuntu.com/security/notices/USN-6587-1
   https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/2051536

Package Information:
   https://launchpad.net/ubuntu/+source/xorg-server/2:21.1.7-3ubuntu2.7
   https://launchpad.net/ubuntu/+source/xorg-server/2:21.1.4-2ubuntu1.7~22.04.8
   https://launchpad.net/ubuntu/+source/xwayland/2:22.1.1-1ubuntu0.11
   https://launchpad.net/ubuntu/+source/xorg-server/2:1.20.13-1ubuntu1~20.04.15