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.
https://jira.atlassian.com/browse/CWD-3366
https://euvd.enisa.europa.eu/vulnerability/EUVD-2013-3857
http://www.commandfive.com/papers/C5_TA_2013_3925_AtlassianCrowd.pdf