TippingPoint Intrusion Prevention System (IPS) TOS before 2.1.4.6324, and TOS 2.2.x before 2.2.1.6506, allow remote attackers to cause a denial of service (CPU consumption) via an unknown vector, probably involving an HTTP request with a negative number in the Content-Length header.
https://exchange.xforce.ibmcloud.com/vulnerabilities/24200
http://www.securityfocus.com/bid/16299
http://www.eweek.com/article2/0%2C1759%2C1912048%2C00.asp
http://securitytracker.com/id?1015511