# CVE-2026-8413: Concrete CMS CSRF in bulk page design controller

Source: https://junglewise.ai/threats/cve-2026-8413-concrete-cms-csrf-in-bulk-page-design-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-2026-8413 · Severity: medium · CVSS 4 · Published 2026-05-21

Concrete CMS, a popular content management system, is vulnerable to a security flaw in its bulk page design tool. This vulnerability could allow an attacker to trick an authorized administrator into performing unintended design changes on multiple pages without their consent. While the impact is limited to unauthorized modifications of page layouts or styles, it could be used to deface parts of a website if a logged-in user visits a malicious link.

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-2026-8413 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-8413 being exploited in the wild.

**How severe is CVE-2026-8413?** 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-2026-8413?** 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-2026-8413 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-8413?** 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/design' component. The application fails to properly validate CSRF tokens or implement sufficient SameSite cookie attributes (CWE-1275) for requests to this endpoint. An unauthenticated remote attacker can exploit this by inducing a logged-in administrator to visit a malicious webpage or click a crafted link. Successful exploitation allows the attacker to perform bulk design changes to pages on behalf of the victim. The issue is resolved in version 9.5.1.

## Affected products

- Concrete CMS Concrete CMS 9.0.0RC1 to 9.5.0

## Identifiers

- CVE-2026-8413
- GHSA-mpq2-mv8p-9wm6

## Timeline

- 2026-05-21: disclosed: NVD Published Date
- 2026-05-22: advisory: GitHub Advisory published
- 2026-06-24: patched: Advisory updated with patch information for version 9.5.1

## 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)