The automatic update feature in Google Talk allows remote attackers to cause a denial of service (CPU and memory consumption) by poisoning a target's DNS cache and causing a large update file to be sent, which consumes large amounts of CPU and memory during the signature verification, aka BenjiBug.
https://exchange.xforce.ibmcloud.com/vulnerabilities/23180
http://marc.info/?l=bugtraq&m=113278119300162&w=2
http://lists.grok.org.uk/pipermail/full-disclosure/2005-November/038969.html