socat 1.2.0.0 before 1.7.2.2 and 2.0.0-b1 before 2.0.0-b6 when used for a listen type address and the fork option is enabled allows remote attackers to cause a denial of service (file descriptor consumption) via multiple request that are refused based on the (1) sourceport (2) lowport (3) range or (4) tcpwrap restrictions.