CVE-2026-8421

8.8 HIGH
Published: May 21, 2026 Modified: May 26, 2026
View on NVD

Description

Concrete CMS 9.5.0 and below contains a CSRF vulnerability in the install_package() method of concrete/controllers/single_page/dashboard/extend/install.php.  An attacker who can cause an authenticated administrator to visit a crafted page,  and who has placed or caused a package to be present under DIR_PACKAGES/<handle>/, can force the installation of that package without any CSRF protection. Package installation executes the package controller's install() method as the web server user, enabling remote code execution.  In order to be vulnerable, the victim must be passing canInstallPackages. 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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory

1 reference(s) from NVD

Quick Stats

CVSS v3 Score
8.8 / 10.0
EPSS (Exploit Probability)
0.2%
7th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

concretecms