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
http://rhn.redhat.com/errata/RHSA-2011-0833.html
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.38