The Java extensions for QuickTime 6.52 and earlier in Apple Mac OS X 10.3.9 allow untrusted applets to call arbitrary functions in system libraries, which allows remote attackers to execute arbitrary code.
http://www.ciac.org/ciac/bulletins/p-312.shtml
http://www.auscert.org.au/5509
http://secunia.com/advisories/16920/
http://lists.apple.com/archives/security-announce/2005/Sep/msg00002.html