USN-6453-2: X.Org X Server vulnerabilities

USN-6453-1 fixed several vulnerabilities in X.Org. This update provides
the corresponding update for Ubuntu 14.04 LTS, Ubuntu 16.04 LTS and
Ubuntu 18.04 LTS.

Original advisory details:

Jan-Niklas Sohn discovered that the X.Org X Server incorrectly handled
prepending values to certain properties. An attacker could possibly use
this issue to cause the X Server to crash, execute arbitrary code, or
escalate privileges. (CVE-2023-5367)

Sri discovered that the X.Org X Server incorrectly handled detroying
windows in certain legacy multi-screen setups. An attacker …

advisory attacker crash issue lts org server ubuntu update usn vulnerabilities x.org