Apache Tomcat before 6.0.39, 7.x before 7.0.50, and 8.x before 8.0.0-RC10 allows attackers to obtain "Tomcat internals" information by leveraging the presence of an untrusted web application with a context.xml, web.xml, *.jspx, *.tagx, or *.tld XML document containing an external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue.