Ingate Firewall before 4.3.4 and SIParator before 4.3.4 allows remote attackers to cause a denial of service (kernel deadlock) by sending a SYN packet for a TCP stream, which requires an RST packet in response.
http://www.vupen.com/english/advisories/2005/3011
http://www.securityfocus.com/bid/16023