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CVE-2026-8140

🔶 medium
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Summary

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 adminis

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.

CVSS Score
6.5
Medium
EPSS Score
0.0
Exploit Probability
Published Date
2026-05-21
First Seen: 2026-05-22
📊 Relative Risk Intelligence

This CVE is Lower Risk - more severe than 47.8% of all 328,009 vulnerabilities in our database.

#171,192
Below average severity
Severity Percentile
🎯 CISA SSVC Assessment Updated: May 22, 2026
🔍 Exploitation Status
None
No known exploits
⚙️ Automatable
NO
Requires human interaction
💥 Technical Impact
Total
Complete system compromise possible
SSVC data provided by CISA
Last Modified 2026-05-26
Source NVD 🔗
CVSS Vector 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
CVSS Vector 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE IDs (Weakness Types)

📦 Affected Products 1

🔗 References 1

🔗 Related CVEs 6

CVE ID Severity CVSS EPSS Summary Published
CVE-2026-8340 🔶 medium 4.3 0.0 Concrete CMS 9.5.0 and below is vulnerable to CSRF via Backend\File::approveVersion. Victim with edit_file_contents p... 2026-05-22
CVE-2026-8347 🔶 medium 4.3 0.0 Concrete CMS 9.5.0 and below is vulnerable to IDOR + wrong-authorization-level in the Express association Reorder dialog... 2026-05-22
CVE-2026-8353 🔶 medium 4.8 0.0 Concrete CMS version 9.0 to 9.5.0 is vulnerable to Stored XSS via page name in the Atomik theme. A rogue editor can inj... 2026-05-22
CVE-2026-6826 🔶 medium 5.3 0.0 Concrete CMS 9.5.0 and below  is vulnerable to unauthenticated file usage disclosure via missing permission check in t... 2026-05-21
CVE-2026-8134 ⚠️ high 7.2 0.5 Concrete CMS 9.5.0 and below fails to sanitize path traversal sequences in the ptComposerFormLayoutSetControlCustomTempl... 2026-05-21
CVE-2026-8135 ⚠️ high 7.2 0.2 Concrete CMS 9.5.0 and below is vulnerable to Remote Code Execution due to insecure deserialization occurring in the E... 2026-05-21
These CVEs affect the same products