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.

Johan Hovold discovered that the DCCP network stack did not correctly
handle certain packet combinations. A remote attacker could send specially
crafted network traffic that would crash the system, leading to a denial of
service.

 kees> May have been introduced as late as 0c10c5d.
 kees> Was possibly fixed briefly by ddab055, but re-introduced by 410e27a.