Many web applications make use of XML-RPC libraries to provide such functionality as pings for RSS feeds. Due to a recently found bug in XML-RPC implementations these applications could now be used to exploit the flaw and compromise the hosting server. Many popular applications ranging from WordPress and PostNuke to PHPwiki are susceptible to the flaw, however most have since been patched to rectify the issue and you need only upgrade. If upgrading is not an option at this time, disabling or upgrading the servers XML-RPC libraries is of paramount importance as exploits are expected in the “wild” any time now. Read more about the problem here.
