# CVE-2026-8350: Concrete CMS privilege escalation in bulk user assignment

Source: https://junglewise.ai/threats/cve-2026-8350-concrete-cms-privilege-escalation-in-bulk-user-assignment  
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-2026-8350 · Severity: high · CVSS 4 · Published 2026-05-21

Concrete CMS, a popular content management system, contains a security flaw in its user management dashboard. An authorized user with access to the bulk user assignment tool can bypass security checks to add themselves or others to the Administrative Group, or even remove existing administrators. This could allow a lower-privileged user to take full control of the website and its data.

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-2026-8350 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-8350 being exploited in the wild.

**How severe is CVE-2026-8350?** High severity, with a CVSS score of 4, published 21 May 2026.

**Which products and versions are affected?** Concrete CMS <= 9.5.0, 9.5.0 and below; concrete5/concrete5 (Packagist) < 9.5.1, ECOSYSTEM:introduced=0,fixed=9.5.1.

**Is there a fix for CVE-2026-8350?** 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-2026-8350 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-8350?** 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 missing authorization check in `bulk_user_assignment.php` allows authenticated users who have access to the bulk user assignment dashboard page to perform unauthorized group modifications. By exploiting this flaw, an attacker can add any user email to any group (including the Administrative Group) and remove legitimate administrators. The vulnerability is categorized as Incorrect Authorization (CWE-863). It requires 'High' privileges to access the dashboard component but allows for a complete compromise of integrity and availability within the CMS. The issue is resolved in version 9.5.1.

## Affected products

- Concrete CMS Concrete CMS <= 9.5.0

## Identifiers

- CVE-2026-8350
- GHSA-g7xp-jf3x-wcx4

## Timeline

- 2026-05-21: disclosed
- 2026-05-21: advisory
- 2026-06-24: patched: Advisory updated with patch details 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

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