High

Concrete CMS is Vulnerable to Cross-Site Request Forgery

  • Disclosed: 21.05.2026
  • Updated: 11.10.2026 10:22

Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($token->output('do_update')) but the corresponding do_update() method in concrete/controllers/single_page/dashboard/system/update/update.php never calls $this->token->validate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string.  In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES.

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-prxr-vjgc-2cq9 - 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. High CVE-2026-8421 < 9.5.1 9.5.1
  2. Concrete CMS is Vulnerable to Cross-Site Request Forgery this entry
    High CVE-2026-8428 < 9.5.1 9.5.1
  3. Critical · 7.2 CVE-2026-8134 < 9.5.1 9.5.1
  4. High · 8.8 CVE-2022-43693 < 8.5.10, >= 9.0.0RC1, < 9.1.3 8.5.10, 9.1.3
  5. High CVE-2021-22954 < 9.0.0 9.0.0
  6. High · 7.2 CVE-2020-11476 < 8.5.3 8.5.3
  7. High · 8.2 CVE-2021-22958 < 8.5.5 8.5.5

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