Don't know if anybody posted this before, but I liked this story.

X-windows, with or without the font server (XFS) running can be crashed remotely via Mozilla when fonts are set to an unnaturally large size with CSS (Cascading Style Sheets), Tom Vogt of Lemuira.org has reported.

An X bug allows all available memory to be consumed, which causes the system to freeze. The behavior can be duplicated with applications like the Gimp, we're told, but these aren't remotely exploitable. But with Mozilla, a pest can easily set up a malicious Web site which will crash unsuspecting Tuxers' boxen and cause any unsaved data in open apps to go away.