CVE-2026-87028

Concrete CMS 9 through 9.5.3 did not confirm that a board InstanceItem submitted to the custom-slot preview endpoint belonged to the board instance the requesting user was authorized to edit, and did not enforce page-view permission before generating page-backed summary content. As a result, an...

CVE-2026-87028 Cross-Board IDOR in the Board Custom Slot Preview in Concrete CMS 9.0.0 through 9.5.3 Discloses Restricted Page Summary Fields

Concrete CMS 9 through 9.5.3 did not confirm that a board InstanceItem submitted to the custom-slot preview endpoint belonged to the board instance the requesting user was authorized to edit, and did not enforce page-view permission before generating page-backed summary content. As a result, an...

CVE-2026-87028 Cross-Board IDOR in the Board Custom Slot Preview in Concrete CMS 9.0.0 through 9.5.3 Discloses Restricted Page Summary Fields

Concrete CMS 9 through 9.5.3 did not confirm that a board InstanceItem submitted to the custom-slot preview endpoint belonged to the board instance the requesting user was authorized to edit, and did not enforce page-view permission before generating page-backed summary content. As a result, an...

CVE-2026-87028: Missing Authorization

Concrete CMS 9 through 9.5.3 did not confirm that a board InstanceItem submitted to the custom-slot preview endpoint belonged to the board instance the requesting user was authorized to edit, and did not enforce page-view permission before generating page-backed summary content. As a result, an...