The dccp_rcv_state_process function in net/dccp/input.c in the Datagram Congestion Control Protocol (DCCP) implementation in the Linux kernel before 2.6.38 does not properly handle packets for a CLOSED endpoint, which allows remote attackers to cause a denial of service (NULL pointer dereference and OOPS) by sending a DCCP-Close packet followed by a DCCP-Reset packet.
http://downloads.avaya.com/css/P8/documents/100145416
http://openwall.com/lists/oss-security/2011/03/08/19
http://openwall.com/lists/oss-security/2011/03/08/4