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.
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.
In Moodle, in some circumstances, email notifications of messages could have the link back to the original message hidden by HTML, which may pose a phishing risk.