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.
docs.info.apple.com/article.html?artnum=307562
lists.apple.com/archives/security-announce/2008/Mar/msg00001.html
secunia.com/advisories/29420
www.securityfocus.com/bid/28304
www.securityfocus.com/bid/28345
www.securitytracker.com/id?1019663
www.us-cert.gov/cas/techalerts/TA08-079A.html
www.vupen.com/english/advisories/2008/0924/references
exchange.xforce.ibmcloud.com/vulnerabilities/41289