Input validation vulnerability in Time Based Greeting 2.2.2

A plugin called Time Based Greeting for WordPress has a security issue called Cross-Site Request Forgery. This affects all versions up to 2.2.2. The problem is that the plugin does not properly check for a security code, making it possible for someone without an account to change settings and insert harmful code on the website if they can trick the person in charge into doing something like clicking a link.