Shopware is an open source eCommerce platform. In versions prior to 6.4.1.1 the admin api has exposed some internal hidden fields when an association has been loaded with a to many reference. Users are recommend to update to version 6.4.1.1. You can get the update to 6.4.1.1 regularly via the Auto-Updater or directly via the download overview. For older versions of 6.1, 6.2, and 6.3, corresponding security measures are also available via a plugin.