CVE-2026-84432 Concrete CMS 9 through 9.5.2 is vulnerable to CSRFin the Boards custom slot dialog controller
Attackers can force users with board-edit permissions to write malicious slot data to boards via cross-site request forgery in Concrete CMS.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-84432?
CVE-2026-84432 is a medium-severity vulnerability in Concrete CMS, published on 10 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Concrete CMS 9 through 9.5.2 did not validate an anti-CSRF token in the Boards custom slot dialog controller (concrete/controllers/dialog/board/custom_slot.php) saveTemplate() action. The action created a board_slot_proxy Block and dispatched an AddCustomSlotToBoardCommand against a board instance while gating only on the per-resource canEditBoardContents() permission, so a crafted cross-site request could cause a user holding board-edit permission with an active session to write attacker-chosen slot and template data to a board under their own authority. The state-changing database write completed before any downstream rendering, so the forged request succeeded even when the HTTP response returned a non-200 status. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.3 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.
Weakness: CWE-352
Which versions are affected by CVE-2026-84432?
How do I fix CVE-2026-84432?
No fix has been published for CVE-2026-84432 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-84432 being exploited?
There is no known exploitation of CVE-2026-84432 in the wild and no public exploit code.
Sources
Also known as GHSA-72w5-w82m-7hm9.