Concrete CmsApplication · Concretecms

CVE-2026-8415

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/express/association/reorder. 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 versions prior to 9.5.0 contain a Cross-Site Request Forgery (CSRF) vulnerability in the Express association reorder endpoint (concrete/controllers/dialog/express/association/reorder). An unauthenticated remote attacker can trick an authenticated user into submitting a crafted request that could result in unauthorized manipulation of Express entity associations, as indicated by the low integrity impact (VI:L) in the CVSS 4.0 vector.

MitigationUpgrade to Concrete CMS version 9.5.0 or later to obtain the security patch. Additionally, implement anti-CSRF tokens or SameSite cookie attributes as a defense-in-depth measure.

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. Identify Concrete CMS version
    Check the version number of your Concrete CMS installation by logging into the admin dashboard and navigating to Dashboard > System & Settings > About Concrete CMS, or check the version file in your installation directory if you have file system access.
    Affected if The installed version is 9.0.0 through 9.5.0 (any version >= 9.0.0 and < 9.5.1)
  2. Verify Express module is enabled
    Navigate to Dashboard > Express > Settings, or check if the Express data model functionality is active on your site.
    Affected if The Express module is enabled and you use Express entities with associations
  3. Confirm administrative access exists
    Review your user permissions to determine if you have administrator-level access to the Express module, as this vulnerability targets authenticated administrators.
    Affected if You have administrator login credentials for the Concrete CMS dashboard
  4. Inspect the reorder endpoint configuration
    Locate the express/association/reorder route handler in your installation (typically in the controller or route configuration files under the express or attributes module) and verify whether the code includes CSRF token validation before processing the reorder request.
    Affected if The reorder endpoint lacks anti-CSRF token validation and accepts requests without verifying a valid token

You are affected if your Concrete CMS version is 9.0.0 through 9.5.0, the Express module is enabled, and the association reorder endpoint is missing CSRF protection validation.

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 version 9.5.0 or later to obtain the security patch. Additionally, implement anti-CSRF tokens or SameSite cookie attributes as a defense-in-depth measure.

Recommended fix High confidence

Concrete CMS 9.5.1 or later

  1. 1. Back up your Concrete CMS database and files before upgrading
  2. 2. Download Concrete CMS version 9.5.1 or later from the official Concrete CMS website or repository
  3. 3. Extract the new version files to your web server, overwriting the existing installation
  4. 4. Run the database upgrade process by accessing your site (the upgrade wizard should automatically prompt you)
  5. 5. Verify the upgrade was successful by logging into the dashboard and checking the version number
  6. 6. Test the express association functionality to confirm the CSRF fix is working correctly
Caveat Review the Concrete CMS 9.5.0 and 9.5.1 release notes for any breaking changes or feature modifications 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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Scan for this in your stack

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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-2026-8415 in production — separate from our analysis above.

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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