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.
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.