Integer signedness error in the Networking component in Apple Mac OS X 10.4 through 10.4.10 allows local users to execute arbitrary code via a crafted AppleTalk message with a negative value, which satisfies a signed comparison during mbuf allocation but is later interpreted as an unsigned value, which triggers a heap-based buffer overflow.
https://exchange.xforce.ibmcloud.com/vulnerabilities/38476
http://lists.apple.com/archives/security-announce/2007/Nov/msg00002.html