Spree 0.11.x before 0.11.2 and 0.30.x before 0.30.0 exchanges data using JavaScript Object Notation (JSON) without a mechanism for validating requests, which allows remote attackers to obtain sensitive information via vectors involving (1) admin/products.json, (2) admin/users.json, or (3) admin/overview/get_report_data, related to a "JSON hijacking" issue.