The Secure Custom Fields WordPress plugin before 6.3.9, Secure Custom Fields WordPress plugin before 6.3.6.3, Advanced Custom Fields Pro WordPress plugin before 6.3.9 does not prevent users from running arbitrary functions through its setting import functionalities, which could allow high privilege users such as admin to run arbitrary PHP functions.

In Advanced Custom Fields (ACF) before 6.3.9 and Secure Custom Fields before 6.3.6.3 (plugins for WordPress), using the Field Group editor to edit one of the plugin's fields can result in execution of a stored XSS payload. NOTE: if you wish to use the WP Engine alternative update mechanism for the free version of ACF, then you can follow the process shown at the advancedcustomfields.com blog URL within the References section below.

The Secure Custom Fields WordPress plugin before 6.9.8 does not verify that a user is allowed to edit the target object before writing to it during bidirectional relationship synchronization, allowing users with contributor-level access and above to add or remove a reference to their own object on arbitrary posts, users, or terms they cannot otherwise edit.

The Secure Custom Fields WordPress plugin before 6.9.8 does not re-apply its field-group location rules when persisting values submitted through the post editor save path, allowing users with contributor-level access and above to write custom fields the site restricted to administrators onto their own posts.