Input validation vulnerability in Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin 1.6.6.1

The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin is a plugin for WordPress websites. It is vulnerable to a type of cyber attack called SQL Injection, which affects versions up to 1.6.6.1. This type of attack allows someone with administrator access to the website to extract sensitive information from the database. This is possible because of the plugin not properly protecting user supplied information and not properly preparing existing SQL queries.