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.

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

Q: 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.

Q: How is CVE-2026-8412 attacked?

It is attacked over the network, in a web application.

Q: 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.

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

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