The Easy Appointments WordPress plugin before 4.0.2.2 does not use an unguessable token to authorize its mail-link appointment cancellation and confirmation action, deriving the token from a hardcoded source-embedded salt and the appointment's creation timestamp, so unauthenticated attackers who know or guess that timestamp can cancel or confirm arbitrary appointments.

The Easy Appointments WordPress plugin before 4.0.1 does not restrict one of its appointment-listing REST endpoints to the records belonging to the requesting user, allowing users with contributor-level access to read all bookings on the site, including customer names, schedules, and statuses.

The Easy Appointments WordPress plugin before 3.12.28 does not perform any capability or nonce check in one of its connection-deletion actions, allowing users with contributor-level access to delete the booking configuration and disable the booking system.