Shopware before 5.3.4 has a PHP Object Instantiation issue via the sort parameter to the loadPreviewAction() method of the ShopwareControllersBackend_ProductStream controller, with resultant XXE via instantiation of a SimpleXMLElement object.
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2017-18357.json"