---
id: CVE-2026-81919
title: >-
  Concrete CMS below 9.5.3 did not validate an anti-CSRF token on the
  block-arrangement backend endpoint (the arrange() action of
  Concrete\Controller\Backend\Page\ArrangeBlocks)
summary: >-
  Concrete CMS below 9.5.3 did not validate an anti-CSRF token on the
  block-arrangement backend endpoint (the arrange() action of
  Concrete\Controller\Backend\Page\ArrangeBlocks). The action enforced page-edit
  authorization but performed no…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N'
cwe:
  - CWE-352
vendor: concretecms
product: concrete_cms
affected:
  - concrete_cms < 9.5.3
patched:
  - concrete_cms 9.5.3
published: '2026-09-15'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T15:26:37.667'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81919'
references:
  - url: >-
      https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes
    label: ff5b8ace-8b95-4078-9743-eac1ca5451de
tags:
  - nvd
  - cve.org
  - score-dispute
epss: 0.00148
epssPercentile: 0.03371
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-15T19:25:21.786485Z'
scores:
  nvd: 4.3
  cna: 2.3
ingestedAt: '2026-09-15T18:41:59.180Z'
---

## Overview

Concrete CMS below 9.5.3 did not validate an anti-CSRF token on the block-arrangement backend endpoint (the arrange() action of Concrete\Controller\Backend\Page\ArrangeBlocks). The action enforced page-edit authorization but performed no token check, and its route accepted any HTTP method, so an attacker could induce a signed-in content editor into loading an attacker-controlled page that auto-submitted a cross-site request and reordered or moved blocks in the draft version of a page the victim was permitted to edit. The default null cookie SameSite configuration let the victim's session cookie accompany the forged request. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.

## Affected

- `concrete_cms < 9.5.3`

## Remediation

Upgrade past the affected range:

- `concrete_cms 9.5.3`