The socket implementation in net/core/sock.c in the Linux kernel before 2.6.34 does not properly manage a backlog of received packets, which allows remote attackers to cause a denial of service (memory consumption) by sending a large amount of network traffic, as demonstrated by netperf UDP tests.
https://bugzilla.redhat.com/show_bug.cgi?id=657303
http://www.vmware.com/security/advisories/VMSA-2011-0012.html
http://www.securityfocus.com/bid/46637
http://www.securityfocus.com/archive/1/520102/100/0/threaded