Incorrect validation of allowed event types in a calendar web service made it possible for some users to create events with types/audiences they did not have permission to publish to.
Separate Groups mode restrictions were not honored in the H5P attempts report, which would display users from other groups. By default this only provided additional access to non-editing teachers.
Separate Groups mode restrictions were not honored when performing a forum export, which would export forum data for all groups. By default this only provided additional access to non-editing teachers.
Insufficient checks in a web service made it possible to add comments to the comments block on another user's dashboard when it was not otherwise available (e.g., on their profile page).
Inadequate access control in Moodle LMS. This vulnerability could allow a local user with a student role to create arbitrary events intended for users with higher roles. It could also allow the attacker to add events to the calendar of all users without their prior consent.