The Downlevel DB2RA Support component in IBM DB2 9.1 before Fixpak 4a allows remote attackers to cause a denial of service (instance crash) via a crafted CONNECT data stream that simulates a V7 client connect request.
https://exchange.xforce.ibmcloud.com/vulnerabilities/45138
http://www.securityfocus.com/bid/29601
http://www-1.ibm.com/support/docview.wss?uid=swg21255607