The Media Gateway Controller (MGC) product is installed on top of Solaris operating system. In the default installation Solaris has several know security vulnerabilites. In order to prevent them from being exploited customers must install updated packages CSCOh007 andCSCOh013. These packages contain the latest Solaris patches and additional hardening of the Solaris OS.
More info at http://www.cisco.com/warp/public/707/Solaris-for-MGC-pub.shtml