Update the WordPress CMS Tree Page View plugin to the latest available version (at least 1.6.8).
LEE SE HYOUNG (hackintoanetwork) discovered and reported this Cross Site Scripting (XSS) vulnerability in WordPress CMS Tree Page View Plugin. This could allow a malicious actor to inject malicious scripts, such as redirects, advertisements, and other HTML payloads into your website which will be executed when guests visit your site. This vulnerability has been fixed in version 1.6.8.