The Java Server Pages (JSP) engine in JRun allows web page owners to cause a denial of service (engine crash) on the web server via a JSP page that calls WPrinterJob().pageSetup(null,null).
http://www.iss.net/security_center/static/9339.php
http://archives.neohapsis.com/archives/vulnwatch/2002-q2/0095.html