https://security-tracker.debian.org/tracker/DSA-5576-1
https://security-tracker.debian.org/tracker/DSA-5576-2
A flaw was found in the way xserver memory was not properly initialized. This could leak parts of server memory to the X client. In cases where Xorg server runs with elevated privileges, this could result in possible ASLR bypass. Xorg-server before version 1.20.9 is vulnerable.
https://security-tracker.debian.org/tracker/DSA-5534-1