An extensive set of X.org vulnerabilities
The X.Org developers have released an advisory warning of a large set of
vulnerabilities in the server, some of which date back to the X11R1 release
in 1987. "How critical these vulnerabilities are to any given installation depends
on whether they run an X server with root privileges or reduced privileges;
whether they run X servers exposed to network clients or limited to local
connections; and whether or not they allow use of the affected protocol
extensions, especially the GLX extension."