wrshdsp.exe in Denicomp Winsock RSHD/NT 2.21.00 and earlier allows remote attackers to cause a denial of service (CPU consumption) via (1) in 2.20.00 and earlier, an invalid port number such as a negative number, which causes a connection attempt to that port and all ports below 1024, and (2) in 2.21.00, a port number of 1024.