Affected: WP Engine Advanced Custom Fields, WP Engine Advanced Custom Fields Pro

Cross-site scripting vulnerability exists in Advanced Custom Fields versions 6.3.5 and earlier and Advanced Custom Fields Pro versions 6.3.5 and earlier. If an attacker with the 'capability' setting privilege which is set in the product settings stores an arbitrary script in the field label, the script may be executed on the web browser of the logged-in user with the same privilege as the attacker's.