GHSA-GMHR-6F43-7QPJ Moodle does not properly implement group-based access restrictions

The coreenrolgetenrolledusers web service in enrol/externallib.php in Moodle through 2.6.11, 2.7.x before 2.7.11, 2.8.x before 2.8.9, and 2.9.x before 2.9.3 does not properly implement group-based access restrictions, which allows remote authenticated users to obtain sensitive course-participant...