The Advanced Custom Fields (ACF) Free and Pro WordPress plugins 6.x before 6.1.0 and 5.x before 5.12.5 unserialize user controllable data, which could allow users with a role of Contributor and above to perform PHP Object Injection when a suitable gadget is present.

The Advanced Custom Fields WordPress plugin before 5.12.3, Advanced Custom Fields Pro WordPress plugin before 5.12.3 allows unauthenticated users to upload files allowed in a default WP configuration (so PHP is not possible) if there is a frontend form available. This vulnerability was introduced in the 5.0 rewrite and did not exist prior to that release.