Executive brief
Concrete CMS is a content management system used to build and manage websites. A flaw in the SEO Bulk Update Meta Tags feature allowed users with limited access to a page to modify that page's metadata (title, description, and URL), even when they lacked edit permissions. This could allow unauthorized changes to how pages appear in search results and on the live website.
Technical details
The SEO Bulk Update Meta Tags editor in Concrete CMS before 9.5.3 fails to enforce per-page edit permissions in the saveRecord() action. While the function validates the CSRF token for the target page, it does not call canEditPageProperties() to check whether the user has edit rights. An authenticated user granted access to the bulk SEO tool can exploit this to modify meta title, meta description, and URL handle for pages they can view but not edit. The vulnerability requires the attacker to have both access to the SEO bulk tool and view permission on the target page. Patched in version 9.5.3.
Affected products
- Concrete CMS Concrete CMS before 9.5.3
Timeline
- 2026-09-15: disclosed