Perfect Survey < 1.5.2 - Unauthorised AJAX Call to Stored XSS / Survey Settings Update

The Perfect Survey WordPress plugin before 1.5.2 does not have proper authorisation nor CSRF checks in the save_global_setting AJAX action, allowing unauthenticated users to edit surveys and modify settings. Given the lack of sanitisation and escaping in the settings, this could also lead to a Stored Cross-Site Scripting issue which will be executed in the context of a user viewing any survey