Based in some recent issues found with the Zend_XmlRpc component of the Zend Framework, the project has release an update, version 1.11.12 that includes a fix for the component to prevent an XXE injection attack.
Zend_XmlRpc is vulnerable to XML eXternal Entity (XXE) Injection attacks. The SimpleXMLElement class (SimpleXML PHP extension) is used in an insecure way to parse XML data. External entities can be specified by adding a specific DOCTYPE element to XML-RPC requests. By exploiting this vulnerability an application may be coerced to open arbitrary files and/or TCP connections.
This security advisory describes the problem as well as the steps taken to correct it and provide the update. It is recommended that anyone using this component upgrade immediately to prevent issues. You can download the latest issue from the Zend Framework download page.