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Concrete CmsApplication · Concretecms

CVE-2026-8411

HIGH · 8.8 CVSS v3.1 Published 2026-05-21
Fix available
A fix is available. Upgrade to 9.5.1 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Concrete CMS 9 before 9.5.0 is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/dialog/page/bulk/delete. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori (Tenzai) for reporting.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Concrete CMS 9 before version 9.5.0 lacks CSRF protection at the page bulk delete endpoint (concrete/controllers/dialog/page/bulk/delete). An attacker can craft a malicious page that, when visited by an authenticated administrator, triggers unintended bulk page deletions via forged requests. The CVSS v4.0 vector indicates low integrity impact (unauthorized deletions) but no confidentiality or availability impact.

MitigationUpgrade to Concrete CMS 9.5.0 or later which includes CSRF token validation at the vulnerable endpoint. Alternatively, implement anti-CSRF tokens on the bulk delete action if upgrading is not immediately feasible.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Concrete CmsApplication
Affected:>= 9.0.0, < 9.5.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed Concrete CMS version
    Locate and inspect the version file or admin dashboard version display. Common locations include a version.php file in the application/config directory or the About page in the dashboard.
    Affected if The installed version is 9.0.0 through 9.5.0 (any version >= 9.0.0 and < 9.5.1)
  2. Verify the affected controller file exists
    Check for the presence of concrete/controllers/dialog/page/bulk/delete.php (or DeleteController.php) in the web root installation directory.
    Affected if The file exists in versions < 9.5.1 and the server is running the vulnerable codebase
  3. Confirm admin access to bulk delete feature
    Log in as an administrator and navigate to the Pages or Dashboard area. Access the bulk operations menu for pages to verify the bulk delete dialog is available.
    Affected if An authenticated administrator user can access the bulk delete functionality in the CMS
  4. Inspect the controller for CSRF protection
    Open the bulk delete controller file (concrete/controllers/dialog/page/bulk/delete.php) and search for anti-CSRF token validation. Look for calls to $this->validateCSRFToken() or similar token validation methods before the delete action executes.
    Affected if The controller lacks CSRF token validation code before the delete operation, indicating vulnerability

You are affected if your Concrete CMS installation is version 9.0.0 through 9.5.0 and administrators can access the bulk delete pages functionality without enforced CSRF token protection.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 9.5.1 or later
Fixed in 9.5.1
Interim mitigation

Upgrade to Concrete CMS 9.5.0 or later which includes CSRF token validation at the vulnerable endpoint. Alternatively, implement anti-CSRF tokens on the bulk delete action if upgrading is not immediately feasible.

Recommended fix High confidence

Concrete CMS 9.5.1 or later

  1. Backup your Concrete CMS database and files before upgrading
  2. Download Concrete CMS version 9.5.1 or later from the official Concrete CMS website or repository
  3. Follow the official upgrade documentation at documentation.concretecms.org to apply the update
  4. Verify the upgrade was successful by logging into the admin dashboard
  5. Test that the bulk delete functionality at concrete/controllers/dialog/page/bulk/delete works correctly post-upgrade
Caveat Review the Concrete CMS 9.5.1 release notes for any breaking changes or migration requirements before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Concrete Cms Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-8411 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data