calendar/managesubscriptions.php in the Manage Subscriptions implementation in Moodle 2.4.x before 2.4.1 omits a capability check, which allows remote authenticated users to remove course-level calendar subscriptions by leveraging the student role and sending an iCalendar object.

mod/wiki/admin.php in Moodle through 2.4.11, 2.5.x before 2.5.9, 2.6.x before 2.6.6, and 2.7.x before 2.7.3 allows remote authenticated users to remove wiki pages by leveraging delete access within a different subwiki.

mod/forum/unsubscribeall.php in Moodle 2.1.x before 2.1.7 and 2.2.x before 2.2.4 does not consider whether a forum is optional, which allows remote authenticated users to bypass forum-subscription requirements by leveraging the student role and unsubscribing from all forums.

mod/data/preset.php in Moodle 2.1.x before 2.1.6 and 2.2.x before 2.2.3 does not properly iterate through an array, which allows remote authenticated users to overwrite arbitrary database activity presets via unspecified vectors.

Moodle 2.0.x before 2.0.9, 2.1.x before 2.1.6, and 2.2.x before 2.2.3 allows remote authenticated users to bypass an activity's read-only state and modify the database by leveraging the student role and editing database activity entries that already exist.

backup/moodle2/restore_stepslib.php in Moodle 2.0.x before 2.0.6 and 2.1.x before 2.1.3 does not check for the moodle/course:changeidnumber privilege during handling of course ID numbers, which allows remote authenticated users to overwrite ID numbers via a restore action.

The default configuration of Moodle 2.0.x before 2.0.2 has an incorrect setting of the moodle/course:delete capability, which allows remote authenticated users to delete arbitrary courses by leveraging the teacher role.

An issue was discovered in Moodle 3.x. By substituting URLs in portfolios, users can instantiate any class. This can also be exploited by users who are logged in as guests to create a DDoS attack.