# CVE-2026-8412: Concrete CMS CSRF in bulk page cache controller

Source: https://junglewise.ai/threats/cve-2026-8412-concrete-cms-csrf-in-bulk-page-cache-controller  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-21. Updated: 2026-06-24  
License: CC BY 4.0 with a link back

CVE-2026-8412 · Severity: medium · CVSS 4 · Published 2026-05-21

Concrete CMS, a popular web content management system, is vulnerable to a security flaw where an attacker can trick an administrator into performing unintended actions. Specifically, if a logged-in administrator visits a malicious website, that site could silently trigger bulk cache operations on the CMS without the user's consent. This could lead to unauthorized changes in how the website handles temporary data, potentially impacting site performance or integrity.

Technologies: [Concrete CMS](https://junglewise.ai/threats/technologies/concrete-cms), [concrete5/concrete5 (Packagist)](https://junglewise.ai/threats/technologies/concrete5-concrete5). Vendors: [Concrete CMS](https://junglewise.ai/threats/vendors/concrete-cms), [Packagist](https://junglewise.ai/threats/vendors/packagist).

## Quick answers

**Is CVE-2026-8412 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-8412 being exploited in the wild.

**How severe is CVE-2026-8412?** Medium severity, with a CVSS score of 4, published 21 May 2026.

**Which products and versions are affected?** Concrete CMS 9.0.0RC1 to 9.5.0; concrete5/concrete5 (Packagist) >= 9.0.0RC1, < 9.5.1, ECOSYSTEM:introduced=9.0.0RC1,fixed=9.5.1.

**Is there a fix for CVE-2026-8412?** Yes. concrete5/concrete5 (Packagist): upgrade to 9.5.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-8412 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-8412?** Check whether you run Concrete CMS or concrete5/concrete5 (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- concrete5/concrete5 (Packagist): upgrade to 9.5.1 or later

  ```sh
  composer require concrete5/concrete5:^9.5.1
  ```


## Technical details

A Cross-Site Request Forgery (CSRF) vulnerability exists in Concrete CMS versions 9.0.0RC1 through 9.5.0 within the 'concrete/controllers/dialog/page/bulk/cache' component. The application fails to properly validate CSRF tokens for requests handled by this controller. An unauthenticated remote attacker can exploit this by enticing a privileged user to visit a specially crafted webpage. If successful, the attacker can execute bulk cache management operations in the context of the victim's session. The issue is resolved in version 9.5.1.

## Affected products

- Concrete CMS Concrete CMS 9.0.0RC1 to 9.5.0

## Identifiers

- CVE-2026-8412
- GHSA-rv3q-xmfw-mcjv

## Timeline

- 2026-05-21: disclosed: NVD publication date
- 2026-05-22: advisory: GitHub Advisory published
- 2026-06-24: patched: Advisory updated with patch details

## References

- [https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes](https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes)

## Related threats

- [Concrete CMS OAuth REST API authorization bypass](https://junglewise.ai/threats/cve-2026-85387-concrete-cms-oauth-rest-api-authorization-bypass)
- [Concrete CMS unauthenticated Express entry search disclosure](https://junglewise.ai/threats/cve-2026-18120-concrete-cms-unauthenticated-express-entry-search-disclosure)
- [Concrete CMS REST API user creation permission bypass](https://junglewise.ai/threats/cve-2026-87031-concrete-cms-rest-api-user-creation-permission-bypass)
- [Concrete CMS access control bypass in board custom-slot preview](https://junglewise.ai/threats/cve-2026-87028-concrete-cms-access-control-bypass-in-board-custom-slot-preview)
- [Concrete CMS stored XSS via XML file upload in Form Block](https://junglewise.ai/threats/cve-2026-85386-concrete-cms-stored-xss-via-xml-file-upload-in-form-block)