Concrete CMS 9.0.0 through 9.5.2 was missing an authorization check on the Express entries advanced-search dashboard action. The advanced_search() method in DashboardSelectableExpressEntryListTrait resolved an Express entity directly from a user-supplied entity ID and rendered that entity's entries without invoking canViewExpressEntries(), the per-entity permission check that the sibling results() action enforced. An authenticated dashboard user holding view_express_entries on a single Express entity could read the entries of any other entity, including secret attribute values, by requesting the advanced-search action with that entity's ID, disclosing form submissions and CRM-style records across the per-entity permission boundary that Express is designed to enforce. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.