CVE-2026-8140 Details
Description
Concrete CMS 9.5.0 and below does not validate a CSRF token before processing requests to /dashboard/extend/install/download/<remoteId>. The download() method in concrete/controllers/single_page/dashboard/extend/install.php checks only the canInstallPackages() permission before fetching a remote marketplace package and writing it to the server's DIR_PACKAGES directory. Because the endpoint is a state-changing GET route with no token enforcement, an attacker who can cause an authenticated administrator to visit a crafted page can force an arbitrary marketplace package to be downloaded. In order to be vulnerable, the victim must be passing canInstallPackages() and the site must be connected to the Concrete marketplace. 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.
A Cross-Site Request Forgery (CSRF) vulnerability has been identified in Concrete CMS versions through 9.5.0. The issue arises in the package download process within the dashboard extension installation feature. The vulnerable endpoint, accessed via a state-changing GET request, lacks proper CSRF token validation. This oversight allows an attacker to manipulate an authenticated administrator into downloading arbitrary marketplace packages, which are then saved to the server's packages directory. For exploitation, the targeted administrator must have the 'canInstallPackages()' permission, and the site must be connected to the Concrete marketplace.
Users can upgrade to Concrete CMS version 9.5.1 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 22, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes | ConcreteCMS | Release Notes |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-352 | Cross-Site Request Forgery (CSRF) | ConcreteCMS |
Affected Products
| Product | Versions |
|---|---|
| concretecms concrete cms | <= 9.5.0 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 23, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | ConcreteCMS |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 26, 2026 | Initial Analysis | [email protected] |
| May 21, 2026 | New CVE Received | ConcreteCMS |