Exposure of Sensitive Information to an Unauthorized Actor
RESTEasy before 2.3.1 allows remote attackers to read arbitrary files via an external entity reference in a DOM document, aka an XML external entity (XXE) injection attack.
CWE-200 - Information Exposure
An information exposure vulnerability is categorized as an information flow (IF) weakness, which can potentially allow unauthorized access to otherwise classified information in the application, such as confidential personal information (demographics, financials, health records, etc.), business secrets, and the application's internal environment.