WP-Cumulus plugin for WordPress is prone to a cross-site scripting vulnerability. It is caused by the application 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 could steal cookie-based authentication credentials, also, implement other attacks.
Update the plugin.
Type XSS (Cross Site Scripting) OWASP Top 10 A3: Cross Site Scripting (XSS)