notifyd in Apple Mac OS X 10.4.11 does not verify that Mach port death notifications have originated from the kernel, which allows local users to cause a denial of service via spoofed death notifications that prevent other applications from receiving notifications.
https://exchange.xforce.ibmcloud.com/vulnerabilities/41289
http://www.vupen.com/english/advisories/2008/0924/references
http://www.us-cert.gov/cas/techalerts/TA08-079A.html
http://www.securitytracker.com/id?1019663
http://www.securityfocus.com/bid/28345
http://www.securityfocus.com/bid/28304
http://secunia.com/advisories/29420
http://lists.apple.com/archives/security-announce/2008/Mar/msg00001.html