The WordPress GDPR plugin for WordPress is vulnerable to unauthorized loss of data due to a missing capability check on the 'WordPress_GDPR_Data_Delete::check_action' function in all versions up to, and including, 2.0.2. This makes it possible for unauthenticated attackers to delete arbitrary users.

The WordPress GDPR plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'gdpr_firstname' and 'gdpr_lastname' parameters in all versions up to, and including, 2.0.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Freemius SDK, as used by hundreds of WordPress plugin and theme developers, was vulnerable to Cross-Site Request Forgery and Information disclosure due to missing capability checks and nonce protection on the _get_debug_log, _get_db_option, and the _set_db_option functions in versions up to, and including 2.4.2. Any WordPress plugin or theme running a version of Freemius less than 2.4.3 is vulnerable.

The check_privacy_settings AJAX action of the WordPress GDPR WordPress plugin before 1.9.27, available to both unauthenticated and authenticated users, responds with JSON data without an "application/json" content-type. Since an HTML payload isn't properly escaped, it may be interpreted by a web browser led to this endpoint. Javascript code may be executed on a victim's browser. Due to v1.9.26 adding a CSRF check, the XSS is only exploitable against unauthenticated users (as they all share the same nonce)

The check_privacy_settings AJAX action of the WordPress GDPR WordPress plugin before 1.9.26, available to both unauthenticated and authenticated users, responds with JSON data without an "application/json" content-type. Since an HTML payload isn't properly escaped, it may be interpreted by a web browser led to this endpoint. Javascript code may be executed on a victim's browser. If the victim is an administrator with a valid session cookie, full control of the WordPress instance may be taken (AJAX calls and iframe manipulation are possible because the vulnerable endpoint is on the same domain as the admin panel - there is no same-origin restriction).