CVE-2021-4385
The WP Private Content Plus plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 3.1. This is due to missing or incorrect nonce validation on the save_groups() function. This makes it possible for unauthenticated attackers to add new group members via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
Source: CVE-2021-4385