CVE-2017-5644: Improper Restriction of Recursive Entity References in DTDs in Apache POI

The vulnerability stems from improper DTD handling in Apache POI's XML parser configuration. The primary vulnerable function is identified as DocumentHelper.createXMLReader() based on: 1) The CVE description specifically mentions OOXML file processing 2) Standard XEE mitigation requires configuring XML parsers with FEATURE_SECURE_PROCESSING 3) Apache POI's security notice references fixes in XML parsing configuration 4) Oracle's security alert links POI's XML handling to this CVE. The createXMLReader method is the logical location for parser configuration in POI's OOXML processing stack.