CVE-2026-8140
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
Concrete CMS version 9.5.0 and below does not validate a CSRF token before processing requests to /dashboard/extend/install/download/<remoteId>. The download() method only checks the canInstallPackages() permission before fetching a remote package and writing it to the DIR_PACKAGES directory. An attacker can force an authenticated administrator to download an arbitrary marketplace package.
Risk Assessment
The risk involves the possibility of an attacker installing a malicious package without the administrator's consent, potentially leading to system integrity compromise and possible control takeover.
Recommendation
It is recommended to immediately upgrade to a version above 9.5.0, which includes a fix enforcing CSRF token validation for this endpoint.
Original NVD description (English source)
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.