IBM Web Traffic Express Caching Proxy Server 3.6 and 4.x before 4.0.1.26 allows remote attackers to cause a denial of service (crash) via an HTTP request to helpout.exe with a missing HTTP version number, which causes ibmproxy.exe to crash.
http://www.securityfocus.com/bid/6002
http://www.iss.net/security_center/static/10452.php
http://www-1.ibm.com/support/search.wss?rs=0&q=IY35970&apar=only