The Salon booking system WordPress plugin before 9.6.3 does not properly sanitize and escape the 'Mobile Phone' field and 'sms_prefix' parameter when booking an appointment, allowing customers to conduct Stored Cross-Site Scripting attacks. The payload gets triggered when an admin visits the 'Bookings' page and the malicious script is executed in the admin context.
https://wpscan.com/vulnerability/3d15f589-956c-4c71-98b1-3ba89d22262c/