The Appointment Hour Booking WordPress plugin before 1.5.88 does not validate a client-supplied booking price against the server-side configured service price, allowing unauthenticated users to submit an arbitrary final price (including zero or negative) that is stored as the authoritative booking price, corrupting booking and payment records.
Credits
Researcher1: Alessandro Greco aka Aleff; Researcher2: Giovambattista Ianni; Company/Organization: University of Calabria (UNICAL)
