Atlassian Confluence before 5.8.17 allows remote authenticated users to read configuration files via the decoratorName parameter to (1) spaces/viewdefaultdecorator.action or (2) admin/viewdefaultdecorator.action.
https://www.exploit-db.com/exploits/39170/
http://www.securityfocus.com/archive/1/537232/100/0/threaded