The Timetable and Event Schedule WordPress plugin before 2.4.2 does not have proper access control when updating a timeslot, allowing any user with the edit_posts capability (contributor+) to update arbitrary timeslot from any events. Furthermore, no CSRF check is in place as well, allowing such attack to be perform via CSRF against a logged in with such capability. In versions before 2.3.19, the lack of sanitisation and escaping in some of the fields, like the descritption could also lead to Stored XSS issues