The Blocks for ACF Fields plugin for WordPress is vulnerable to unauthorized access of data due to a missing capability check on the get_all_values() function in the /wp-json/acf-field-blocks/v1/values REST endpoint in versions up to, and including, 1.6.2. The permission_callback only verifies the generic publish_posts capability and the handler passes a user-supplied id parameter directly to get_field_objects() without verifying that the requesting user is authorized to read the target object. This makes it possible for authenticated attackers, with Author-level access and above, to read ACF field values from arbitrary posts (including private posts, drafts, posts by other users, and other ACF-supported objects) that they should not have access to.
https://plugins.trac.wordpress.org/browser/acf-field-blocks/tags/1.6.0/inc/class-rest.php#L302
https://plugins.trac.wordpress.org/browser/acf-field-blocks/tags/1.6.0/inc/class-rest.php#L296
https://plugins.trac.wordpress.org/browser/acf-field-blocks/tags/1.6.0/inc/class-rest.php#L100
https://plugins.trac.wordpress.org/browser/acf-field-blocks/tags/1.5.0/inc/class-rest.php#L302
https://plugins.trac.wordpress.org/browser/acf-field-blocks/tags/1.5.0/inc/class-rest.php#L296
https://plugins.trac.wordpress.org/browser/acf-field-blocks/tags/1.5.0/inc/class-rest.php#L100