Is CVE-2026-8416 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-8416 being exploited in the wild.

How severe is CVE-2026-8416?

Medium severity, with a CVSS score of 4, published 21 May 2026.

Which products and versions are affected?

Concrete CMS 9.0.0 to 9.4.8, 9.0.0RC1 through 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-2026-8416?

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-2026-8416 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-8416?

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.

CVE-2026-8416: Concrete CMS CSRF in addFavoriteFolder backend controller

Q: Is there a fix for CVE-2026-8416?

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.

Q: How is CVE-2026-8416 attacked?

It is attacked over the network, in a network appliance.

Q: Am I affected by CVE-2026-8416?

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.

CVE-2026-8416 · Severity: medium · CVSS 4 · Published 2026-05-21

Concrete CMS is a popular open-source content management system used for building and managing websites. A security flaw in the file management component allows an attacker to trick a logged-in user into performing unintended actions, specifically adding folders to their 'favorites' list. While this particular issue has low direct impact on data security, it represents a failure in the system's request validation that could be used in more complex social engineering attacks.

Technologies: Concrete CMS, concrete5/concrete5 (Packagist). Vendors: Concrete CMS, Packagist.

Quick answers

Is CVE-2026-8416 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-8416 being exploited in the wild.
How severe is CVE-2026-8416?: Medium severity, with a CVSS score of 4, published 21 May 2026.
Which products and versions are affected?: Concrete CMS 9.0.0 to 9.4.8, 9.0.0RC1 through 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-2026-8416?: 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-2026-8416 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-8416?: 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
```
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 'addFavoriteFolder' method of the backend file controller. The application fails to validate CSRF tokens or implement sufficient SameSite cookie attributes when processing requests to 'concrete/controllers/backend/file'. An attacker can exploit this by inducing an authenticated user to visit a malicious webpage, which then triggers a background request to add a specific folder ID to the user's favorites. This vulnerability is addressed in version 9.5.1 by implementing proper request validation.

Affected products

Concrete CMS Concrete CMS 9.0.0RC1 through 9.5.0

Identifiers

CVE-2026-8416
GHSA-qj94-6rx6-27fr

Timeline

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

References

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

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