Buffer overflow in XFree86 3.3.x allows local users to execute arbitrary commands via a long -xkbmap parameter.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2000-0284
http://www.securityfocus.com/bid/1306
http://archives.neohapsis.com/archives/bugtraq/2000-04/0076.html