---
id: CVE-2026-81902
title: >-
  Concrete CMS 9 through 9.5.2 did not validate a CSRF token in the orphaned
  block removal panel action (removeOrphanedBlocks)
summary: >-
  Concrete CMS 9 through 9.5.2 did not validate a CSRF token in the orphaned
  block removal panel action (removeOrphanedBlocks). A remote attacker could
  craft a request that, when loaded by an authenticated user holding edit
  permission on t…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H'
cwe:
  - CWE-352
vendor: concretecms
product: concrete_cms
affected:
  - 'concrete_cms >= 9.0.0, < 9.5.3'
patched:
  - concrete_cms 9.5.3
published: '2026-09-14'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T19:13:05.493'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81902'
references:
  - url: >-
      https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes
    label: ff5b8ace-8b95-4078-9743-eac1ca5451de
tags:
  - nvd
  - cve.org
epss: 0.0024
epssPercentile: 0.1338
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-15T14:23:51.380448Z'
scores:
  nvd: 8.1
  cna: 7.1
ingestedAt: '2026-09-14T21:15:17.560Z'
---

## Overview

Concrete CMS 9 through 9.5.2 did not validate a CSRF token in the orphaned block removal panel action (removeOrphanedBlocks). A remote attacker could craft a request that, when loaded by an authenticated user holding edit permission on the target page, deleted every block on that page's current version; blocks not aliased to another page or scrapbook entry were also removed from the global Blocks table and their block-type data table, permanently destroying the content. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.1 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.

## Affected

- `concrete_cms >= 9.0.0, < 9.5.3`

## Remediation

Upgrade past the affected range:

- `concrete_cms 9.5.3`