WordPress All-in-One Event Calendar plugin's/wp-content/plugins/all-in-one-event-calendar/app/view/box_publish_button.php "button_value" parameter is prone to a cross-site scripting vulnerability. It fails to properly clean up user-supplied input. An attacker may execute arbitrary script code in the browser of an user in the context of the affected site. In this way the attacker can steal cookie-based authentication credentials. Other attacks are also possible.
Update the plugin.
Type XSS (Cross Site Scripting) OWASP Top 10 A3: Cross Site Scripting (XSS)