---
id: CVE-2026-84432
title: >-
  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
summary: >-
  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 disp…
severity: medium
cvss: 5.3
cvssVector: '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'
cwe:
  - CWE-352
vendor: Concrete CMS
product: Concrete CMS
affected:
  - concrete_cms >= 9.0.0 <= 9.5.2
published: '2026-09-10'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T20:44:57.447'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84432'
references:
  - url: >-
      https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes
    label: ff5b8ace-8b95-4078-9743-eac1ca5451de
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-10T19:27:45.588429Z'
cvssSource: cna
ingestedAt: '2026-09-14T14:16:56.757Z'
epss: 0.00239
epssPercentile: 0.13248
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.