The Express Entries Dashboard in Concrete5 8.5.4 allows stored XSS via the name field of a new data object at an index.php/dashboard/express/entries/view/ URI.
Concrete5 up to and including 8.5.2 allows Unrestricted Upload of File with Dangerous Type such as a .php file via File Manager. It is possible to modify site configuration to upload the PHP file and execute arbitrary commands.
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.
Cross-site scripting (XSS) vulnerability in single_pages\download_file.php in concrete5 before 5.6.3 allows remote attackers to inject arbitrary web script or HTML via the HTTP Referer header to index.php/download_file.