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Concrete CmsApplication · Concretecms

CVE-2023-28476

MEDIUM · 5.4 CVSS v3.1 Published 2023-04-28
Fix available
A fix is available. Upgrade to 9.2.0 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

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 (previously concrete5) in versions 9.0 through 9.1.3 is vulnerable to Stored XSS on Tags on uploaded files.

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 9.0 through 9.1.3 contains a stored cross-site scripting (XSS) vulnerability in the Tags field associated with uploaded files, allowing authenticated attackers to inject malicious JavaScript that executes when other users view or access those tagged files.

MitigationUpgrade Concrete CMS to version 9.1.4 or later which addresses this stored XSS vulnerability in the file tags 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:< 9.2.0

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
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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 installed Concrete CMS version
    Access the dashboard and navigate to System & Settings > About Concrete CMS, or check the version number in the footer of any admin page. Alternatively, check the file concrete/config/version.php for the VERSION constant.
    Affected if The installed version is 9.0, 9.1.0, 9.1.1, 9.1.2, or 9.1.3 (any version from 9.0 through 9.1.3).
  2. Verify file manager access exists
    Navigate to the File Manager (Dashboard > Files > Files) to confirm the file tagging functionality is accessible in the environment.
    Affected if Users with file upload permissions can access the File Manager and add tags to files.
  3. Inspect database for existing file tags
    Query the FileSetEntries or similar file tag-related database tables (check for tables containing 'File' and 'Tag' or 'Attribute' in the concrete5 database) to see if custom tags have been added to any files.
    Affected if Any files exist with custom tags stored in the database, as these tags are rendered without proper sanitization in affected versions.
  4. Review recent file uploads for suspicious tags
    In the File Manager, review recent file entries and examine the Tags attribute field for any tags containing HTML, JavaScript, or unusual characters like <, >, script, or javascript:.
    Affected if Any tags contain potentially malicious JavaScript payload content that could execute when files are viewed.

A user is affected if their Concrete CMS installation runs version 9.0 through 9.1.3 and the File Manager with tagging functionality is accessible and in use.

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 9.2.0 or later
Fixed in 9.2.0
Interim mitigation

Upgrade Concrete CMS to version 9.1.4 or later which addresses this stored XSS vulnerability in the file tags functionality.

Recommended fix High confidence

9.2.0

  1. Backup the database and all files before upgrading
  2. Download Concrete CMS version 9.2.0 or later from the official Concrete CMS website (concretecms.com)
  3. Follow the official Concrete CMS upgrade documentation for migrating from version 9.x
  4. Upload the new version files to the server, overwriting existing files
  5. Run the database upgrade script through the CMS interface or command line
  6. Verify the upgrade was successful by logging into the admin panel
  7. Confirm the version number displays as 9.2.0 or later in the dashboard
Caveat Review the Concrete CMS 9.2.0 release notes for any deprecations or configuration changes before upgrading in production

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

Fix this in Concrete Cms Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,190
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,904.

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-2023-28476 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