In REDAXO before 5.6.3, a critical SQL injection vulnerability has been discovered in the rex_list class because of the prepareQuery function in core/lib/list.php, via the index.php?page=users/users sort parameter. Endangered was the backend and the frontend only if rex_list were used.
Cross-site scripting (XSS) vulnerability in include/classes/class.rex_list.inc.php in REDAXO 4.3.x and 4.4 allows remote attackers to inject arbitrary web script or HTML via the subpage parameter to index.php.