During a security research I found an authenticated Stored XSS vulnerability.
The name of the plugin is: DSGVO All in one for WP < 4.1
The plugin does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)
Go the DSGVO AIO > Settings Cookie Notice settings and enabled them, then put the following payload in any of the Button Text settings (such as "Button Text (Accept)", "Button Text (Personalize)" and "Button Text (Reject)"): <img src onerror=alert(/XSS/)> The XSS will be trigged in any frontend page
Plugin has more than 20,000+ active installations.