Improper Restriction of XML External Entity Reference
Apache PDFBox before 2.0.15 does not properly initialize the XML parser, which allows context-dependent attackers to conduct XML External Entity (XXE) attacks via a crafted XFDF.
CWE-611 - Improper Restriction of XML External Entity Reference
Listed 4th in the 'OWASP Top Ten', XML External Entities (XXE) vulnerability allows attackers to provide an XML input that contains an external entity. When the XML is parsed, it can cause data extraction and manipulation, execution of commands, denial-of-service attacks, and server-side request forgery.