CVE-2026-18425

IDOR in Concrete CMS 9.0.0 through 9.5.2 dashboard sitemap reorder (SitemapUpdate::updateDisplayOrder) allows an authenticated sitemap user to reorder arbitrary pages

Concrete CMS 9 before 9.5.3 authorized the dashboard sitemap reorder action (Concrete\Controller\Backend\Dashboard\SitemapUpdate) using only the global access_sitemap task permission and did not check per-page edit permission before updating each page's display order. As a result, an authenticated user granted sitemap access could change the display order (cDisplayOrder) of any pages they had no rights to edit, altering the order in which those pages render in navigation, breadcrumb, and page-list output. The reorder action additionally validated no CSRF token, so the write could be triggered by a forged request. 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:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.