The XML Parser Test Suite can be used to test the robustness, security, and reliability of XML parsers. An XML parser is a software module whose purpose is to read XML data and extract application data to be handled within the actual application. The reliability and security of the XML parser used in a system are critical for the overall system reliability and security. A parser touches incoming requests usually without any prior authentication or screening so vulnerabilities in the parser are usually directly exploitable for denial-of-service attacks or worse.