High

Concrete CMS contains a CSRF vulnerability

  • Disclosed: 21.05.2026
  • Updated: 11.10.2026 10:22

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 thanks @maru1009 for reporting this issue.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Composer package concrete5/concrete5 < 9.5.1 9.5.1

References

CVSS score -
CVSS 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
Weakness (CWE)
CWE-352
Platform
Composer
Package
concrete5/concrete5
Disclosed
21.05.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-4c8m-6fwx-m7xq - CC BY 4.0

Vulnerability history: concrete5/concrete5

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (121) in the archive
Total entries
121
First → latest
10.2021 06.2026
Without a fix
10
Exploited in attacks
0

Severity breakdown

  • Critical 2
  • High 16
  • Medium 65
  • Low 38

Disclosures per year

  1. 2021: 2
  2. 2022: 18
  3. 2023: 21
  4. 2024: 21
  5. 2025: 5
  6. 2026: 54
Severity:
  1. Concrete CMS contains a CSRF vulnerability this entry
    High CVE-2026-8421 < 9.5.1 9.5.1
  2. Critical · 7.2 CVE-2026-8134 < 9.5.1 9.5.1
  3. High · 8.8 CVE-2022-43693 < 8.5.10, >= 9.0.0RC1, < 9.1.3 8.5.10, 9.1.3
  4. High CVE-2021-22954 < 9.0.0 9.0.0
  5. High · 7.2 CVE-2020-11476 < 8.5.3 8.5.3
  6. High · 8.2 CVE-2021-22958 < 8.5.5 8.5.5

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