CVE 2007-0613
The Bonjour functionality in mDNSResponder, iChat 3.1.6, and InstantMessage framework 428 in Apple Mac OS X 10.4.8 does not check for duplicate entries when adding newly discovered available contacts, which allows remote attackers to cause a denial of service (disrupted communication) via a flood of duplicate _presence._tcp mDNS queries.
See the
CVE page on Mitre.org
for more details.