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 hardcode…

Summary

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.