CVE-2026-8428
Analyzed
Analyzed - Analysis Complete
CSRF Bypass Leading to Arbitrary CMS Update in Concrete CMS
Publication date: 2026-05-21
Last updated on: 2026-05-26
Assigner: ConcreteCMS
Description
Description
Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($token->output('do_update')) but the corresponding do_update() method in concrete/controllers/single_page/dashboard/system/update/update.php never calls $this->token->validate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string. In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES. 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.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| concretecms | concrete_cms | to 9.5.1 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-352 | The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor. |
| CWE-829 | The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere. |
