dbcve.org
Concrete CmsApplication · Concretecms

CVE-2021-22950

MEDIUM · 6.5 CVSS v3.1 Published 2021-09-23
Fix available
A fix is available. Upgrade to 8.5.6 or later.
See remediation →
72/100
Remediation priority · Elevated
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 prior to 8.5.6 had a CSFR vulnerability allowing attachments to comments in the conversation section to be deleted.Credit for discovery: "Solar Security Research Team"

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 8.5.6 contained a Cross-Site Request Forgery (CSRF) vulnerability in the conversation/comments section. The application failed to validate anti-CSRF tokens on the comment attachment deletion endpoint, allowing attackers to craft malicious requests that trick authenticated users into deleting attachments without their knowledge or consent.

MitigationUpgrade to Concrete CMS version 8.5.6 or later, which includes proper CSRF token validation for the attachment deletion functionality.

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:< 8.5.6

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
None
Integrity
High
Availability
None

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

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
    Log into the dashboard and navigate to Dashboard > System & Settings > Basics > Maintenance Mode, or check the application/config/version.php file for the version number
    Affected if The version number is less than 8.5.6 (for example, 8.5.5, 8.5.4, etc.)
  2. Verify conversation feature is enabled
    Navigate to Dashboard > System & Settings > Conversation Settings, or check if the 'conversation' feature is listed in the site's active features
    Affected if Conversations and comments are enabled on the site, allowing users to post comments on pages
  3. Check if the site uses comment attachments
    Review pages that allow user comments and check if the attachment upload feature is available in the comment form
    Affected if The comment attachment functionality is active and users can upload files to comments
  4. Inspect the attachment deletion endpoint for CSRF protection
    Locate the file handling comment deletion in the codebase (typically in controllers or handlers for conversation attachments) and examine whether the delete action validates an anti-CSRF token before processing the request
    Affected if The attachment deletion code does not call the CSRF validation function (such as $this->validateCSRFToken() or similar) before processing the deletion request

You are affected if your Concrete CMS version is below 8.5.6 and the conversation/comments feature with attachment support is enabled on your site.

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 8.5.6 or later
Fixed in 8.5.6
Interim mitigation

Upgrade to Concrete CMS version 8.5.6 or later, which includes proper CSRF token validation for the attachment deletion functionality.

Recommended fix High confidence

Concrete CMS 8.5.6

  1. Backup your Concrete CMS database and files before proceeding
  2. Download Concrete CMS version 8.5.6 from the official concretecms.org website
  3. Follow the standard Concrete CMS upgrade procedure: upload the new files and run the upgrade script
  4. After upgrade, verify the installation is working correctly
  5. Confirm the conversation/attachment deletion functionality works as expected
Caveat No specific breaking changes mentioned in the available documentation for this security update

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
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-22950 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2021-22950 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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