Is CVE-2026-8409 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-8409 being exploited in the wild.

How severe is CVE-2026-8409?

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 (before 9.5.0), 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-2026-8409?

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-2026-8409 attacked?

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

Am I affected by CVE-2026-8409?

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-2026-8409: Concrete CMS CSRF in log deletion controller

Q: Is there a fix for CVE-2026-8409?

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-2026-8409 attacked?

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

Q: Am I affected by CVE-2026-8409?

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-2026-8409 · Severity: medium · CVSS 4 · Published 2026-05-21

Concrete CMS is a content management system used to build and manage websites. A security flaw in the log management component allows an attacker to trick an administrator into unintentionally deleting system logs. This could be used by an attacker to hide their tracks after performing other malicious activities on the site.

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

Quick answers

Is CVE-2026-8409 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-8409 being exploited in the wild.
How severe is CVE-2026-8409?: 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 (before 9.5.0), 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-2026-8409?: 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-2026-8409 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-8409?: 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/logs/delete' component. The application fails to properly validate CSRF tokens or implement sufficient SameSite cookie attributes for requests to the log deletion endpoint. An unauthenticated attacker can exploit this by inducing a logged-in administrator to visit a malicious webpage, leading to the unauthorized deletion of system logs. This vulnerability is tracked as CVE-2026-8409 and has been addressed in version 9.5.1.

Affected products

Concrete CMS Concrete CMS 9.0.0RC1 through 9.5.0

Identifiers

CVE-2026-8409
GHSA-56c9-xq5g-xrf9

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

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