lib/moodlelib.php in Moodle through 2.6.11, 2.7.x before 2.7.10, 2.8.x before 2.8.8, and 2.9.x before 2.9.2 relies on the PHP mt_rand function to implement the random_string and complex_random_string functions, which makes it easier for remote attackers to predict password-recovery tokens via a brute-force approach.
In Moodle 3.2.x, global search displays user names for unauthenticated users.
In Moodle 2.x and 3.x, the question engine allows access to files that should not be available.
Moodle 3.0 through 3.0.3, 2.9 through 2.9.5, and 2.8 through 2.8.11 allows remote attackers to obtain the names of hidden forums and forum discussions.