Easy!Appointments is a self hosted appointment scheduler. Versions prior to 1.6.0 allow administrators to define a custom "booking disabled" message through the booking settings page. That value is stored in the `disable_booking_message` setting via a rich-text editor and later passed directly to the public `booking_message` view without escaping or sanitization. An authenticated administrator can store HTML or JavaScript in this field, enable disabled-booking mode, and trigger stored XSS in every unauthenticated visitor who opens the public booking page. Version 1.6.0 fixes the issue.

Affected: Packagist: alextselegidis/easyappointments

## Summary Easy!Appointments allows administrators to define a custom "booking disabled" message through the booking settings page. That value is stored in the `disable_booking_message` setting via a rich-text editor and later passed directly to the public `booking_message` view without escaping or sanitization: ```php <p><?= vars('message_text') ?></p> ``` An authenticated administrator can store HTML or JavaScript in this field, enable disabled-booking mode, and trigger stored XSS in every unauthenticated visitor who opens the public booking page. --- ## Root Cause — Step by Step Code Flow ### Step 1 — Rich text editor value stored without sanitization The booking settings page collects the message value from the Trumbowyg rich-text editor and submits it as raw HTML: ```javascript // assets/js/pages/booking_settings.js line 61-92 bookingSettings.push({ name: 'disable_booking_message', value: $disableBookingMessage.trumbowyg('html'), }); ``` ### Step 2 — Settings controller saves value verbatim The backend settings controller persists the submitted value without any HTML sanitization: ```php // application/controllers/Booking_settings.php line 76-104 $this->settings_model->save($setting); ``` ### Step 3 — Public booking controller forwards stored value to view When booking is disabled, the public booking controller loads the stored message and passes it directly to the view: ```php // application/controllers/Booking.php line 113-132 $disable_bo…