Update the WordPress Modern Events Calendar Lite plugin to the latest available version (at least 6.5.2).
Muhammad Daffa discovered and reported this Cross Site Scripting (XSS) vulnerability in WordPress Modern Events Calendar Lite 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 6.5.2.