IBM WebSphere Application Server 7.x before 7.0.0.39, 8.0.x before 8.0.0.11, and 8.5.x before 8.5.5.7 and WebSphere Virtual Enterprise before 7.0.0.7 allow remote attackers to obtain potentially sensitive information about the proxy-server software by reading the HTTP Via header.
http://www.securitytracker.com/id/1033325
http://www.securityfocus.com/bid/76466