lib/ajax/getnavbranch.php in Moodle through 2.6.11, 2.7.x before 2.7.13, 2.8.x before 2.8.11, 2.9.x before 2.9.5, and 3.0.x before 3.0.3, when the forcelogin feature is enabled, allows remote attackers to obtain sensitive category-detail information from the navigation branch by leveraging the guest role for an Ajax request.
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.