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Concrete CmsApplication · Concretecms

CVE-2021-22967

HIGH · 7.5 CVSS v3.1 Published 2021-11-19
Fix available
A fix is available. Upgrade to 8.5.7 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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
In Concrete CMS (formerly concrete 5) below 8.5.7, IDOR Allows Unauthenticated User to Access Restricted Files If Allowed to Add Message to a Conversation.To remediate this, a check was added to verify a user has permissions to view files before attaching the files to a message in "add / edit message”.Concrete CMS security team gave this a CVSS v3.1 score of 4.3 AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NCredit for discovery Adrian H

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

This is an IDOR (Insecure Direct Object Reference) vulnerability in Concrete CMS versions below 8.5.7. The flaw allows unauthenticated users to access restricted files through the conversation/message system by exploiting a missing permission check when attaching files to messages. An attacker could potentially view files they should not have access to by manipulating file attachment functionality.

MitigationUpgrade Concrete CMS to version 8.5.7 or later, which adds a permission check to verify users can view files before allowing them to be attached to messages.

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:< 8.5.7

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
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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. Identify Concrete CMS version
    Locate the version number in the dashboard (Dashboard > System & Settings > Basics > Site Information) or check the CHANGELOG.md file in the web root
    Affected if version is 8.5.6 or earlier (below 8.5.7)
  2. Confirm conversation system is active
    Check if the messaging/conversation feature is enabled in Dashboard > System & Settings > Permissions > Access Entity Types or if users can send messages to each other
    Affected if the conversation system is in use and users can exchange messages
  3. Verify file attachments are permitted
    Check if file attachments are enabled for messages by attempting to attach a file to a message, or review Dashboard > System & Settings > Files > File Storage Locations
    Affected if file attachments can be added to messages
  4. Test for unauthorized file access
    Attempt to access files through the message attachment system using a different user account with restricted permissions, observing if files outside the user's permissions are accessible
    Affected if a user can view attached files they should not have permission to access

A user is affected if running Concrete CMS version 8.5.6 or earlier with the conversation messaging system enabled and file attachments permitted.

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 8.5.7 or later
Fixed in 8.5.7
Interim mitigation

Upgrade Concrete CMS to version 8.5.7 or later, which adds a permission check to verify users can view files before allowing them to be attached to messages.

Recommended fix High confidence

Concrete CMS 8.5.7 or later

  1. Back up your Concrete CMS database and files before upgrading
  2. Download Concrete CMS version 8.5.7 or later from the official source (concretecms.com)
  3. Extract the new version files
  4. Replace the core CMS files on your server with the new version files, preserving your site-specific configuration
  5. Run any available database migrations if required by the upgrade
  6. Verify the site functions correctly after the upgrade
  7. Confirm the IDOR vulnerability is remediated by testing that unauthenticated users cannot access restricted files through conversation messages

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
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,808.

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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-2021-22967 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