An issue was discovered in tools/conversations/view_ajax.php in Concrete5 before 8.3.0. An unauthenticated user can enumerate comments from all blog posts by POSTing requests to /index.php/tools/required/conversations/view_ajax with incremental 'cnvID' integers.
DLP 15.5 MP1 and all prior versions may be susceptible to a cross-site scripting (XSS) vulnerability, a type of issue that can enable attackers to inject client-side scripts into web pages viewed by other users. A cross-site scripting vulnerability may be used by attackers to bypass access controls such as the same-origin policy.