CVE-2026-8417: concrete cms CSRF (CVSS 8.8)

Description

Concrete CMS 9.5.0 and below does not validate a CSRF token before processing requests to /dashboard/extend/update/do_update/<pkgHandle>. The do_update() method in concrete/controllers/single_page/dashboard/extend/update.php checks only canInstallPackages() before executing upgradeCoreData() and upgrade() on the named package's controller. Because the endpoint is a state-changing GET route with no token enforcement, an attacker can force an authenticated administrator to trigger a package upgrade via a single cross-site navigation.In order to be vulnerable, the victim must be passing canInstallPackages() and and a target package must already be already installed. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.

Is your site exposed to CVE-2026-8417?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0012

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-352 Cross-Site Request Forgery

Affected Products

Vendor	Product	Versions
concretecms	concrete_cms	< 9.5.1

References

Other References

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

Frequently Asked Questions

What is CVE-2026-8417? +

Concrete CMS 9.5.0 and below does not validate a CSRF token before processing requests to /dashboard/extend/update/do_update/<pkgHandle>. The do_update() method in concrete/controllers/single_page/dashboard/extend/update.php checks only canInstallPackages() before executing upgradeCoreData() and upgrade() on the named package's controller. Because the endpoint is a state-changing GET route with no token enforcement, an attacker can force an authenticated administrator to trigger a package upgrade via a single cross-site navigation.In order to be vulnerable, the victim must be passing canInstallPackages() and and a target package must already be already installed. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-8417? +

CVE-2026-8417 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0012, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-8417? +

CVE-2026-8417 affects products from concretecms, specifically: concrete_cms. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-8417? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-40325

Masa CMS is a content management system forked from Mura CMS. In versions 7.5.2 and earlier, the `cTrash.restore` function does …

CVE-2026-40174

Masa CMS is a content management system forked from Mura CMS. In versions 7.5.2 and earlier, the cUsers.updateAddress function does …

CVE-2024-6662

Websites managed by MegaBIP in versions below 5.15 are vulnerable to Cross-Site Request Forgery (CSRF) as the form available under …

CVE-2026-42286

Emlog is an open source website building system. Prior to version 2.6.11, missing CSRF protection in critical admin functions allows …

CVE-2026-9591

Cross-site request forgery (CSRF) in NewsItemApiController in SimplCommerce prior to commit 6233d73e allows an unauthenticated remote attacker to create or …

CVE-2024-7141

Versions of Gliffy Online prior to versions 4.14.0-7 contains a Cross Site Request Forgery (CSRF) flaw.

CVE-2026-8417