Atlassian Crowd 2.5.x before 2.5.4, 2.6.x before 2.6.3, 2.3.8, and 2.4.9 allows remote attackers to read arbitrary files and send HTTP requests to intranet servers via a request to (1) /services/2 or (2) services/latest with a DTD containing an XML external entity declaration in conjunction with an entity reference.