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Crafter CmsApplication · Craftercms

CVE-2021-23260

MEDIUM · 5.4 CVSS v3.1 Published 2021-12-02
Fix available
A fix is available. Upgrade to 3.1.12 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
Authenticated users with Site roles may inject XSS scripts via file names that will execute in the browser for this and other users of the same site.

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 · moderate confidence

This is a stored Cross-Site Scripting (XSS) vulnerability where authenticated users with Site roles can inject malicious scripts through file names. When other users of the same site view or interact with files containing crafted XSS payloads in their names, the script executes in their browsers, potentially allowing session hijacking, data theft, or actions on behalf of victims.

MitigationImplement strict input validation and output encoding for all file names, ensuring special characters are properly sanitized before storage and before rendering in any user-accessible interface. Consider implementing a Content Security Policy (CSP) header 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
Crafter CmsApplication
Affected:>= 3.1.0, < 3.1.12

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 CrafterCMS version
    Locate the version file or startup logs typically found in the installation directory (such as version.txt or in the startup logs). Alternatively, check the admin dashboard or API endpoint that exposes version information.
    Affected if The installed version is 3.1.0, 3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.1.5, 3.1.6, 3.1.7, 3.1.8, 3.1.9, 3.1.10, or 3.1.11 (any version >= 3.1.0 but < 3.1.12).
  2. Audit existing file names for XSS payloads
    Query the content repository or file system for file names containing script tags, javascript:, on* event handlers (onclick, onerror, onload), or other common XSS patterns. Use search commands or database queries to scan asset file names across all sites.
    Affected if Any file names exist that contain unsanitized HTML/JavaScript content such as <script>, javascript:, img onerror=, or similar XSS vectors.
  3. Review Site role user access
    Check the user management console or database to identify users assigned the Site role. Determine if these users have permissions to upload or rename files within sites.
    Affected if Users with Site role permissions exist and have the ability to upload or modify file names in the system.
  4. Inspect file rendering interfaces
    Test the file preview, asset browser, or file listing interfaces by creating a test file with a benign XSS probe in the name (such as test<img src=x onerror=alert(1)>). View the file through the UI to verify if the name is rendered without encoding.
    Affected if File names are displayed in the UI without proper HTML entity encoding, allowing script execution when viewed.

You are affected if your CrafterCMS version is 3.1.0 through 3.1.11 AND users with Site roles can upload or rename files AND those file names are rendered in browsers without encoding.

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 3.1.12 or later
Fixed in 3.1.12
Interim mitigation

Implement strict input validation and output encoding for all file names, ensuring special characters are properly sanitized before storage and before rendering in any user-accessible interface. Consider implementing a Content Security Policy (CSP) header as a defense-in-depth measure.

Recommended fix Moderate confidence

Crafter CMS 3.1.12

  1. Backup your current Crafter CMS installation and database
  2. Download Crafter CMS version 3.1.12 or later from the official Crafter CMS downloads page
  3. Stop the Crafter CMS services
  4. Deploy the new version following the standard Crafter CMS upgrade procedure
  5. Restart Crafter CMS services
  6. Verify the upgrade was successful by logging in and testing file upload functionality

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

Fix this in Crafter Cms Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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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-2021-23260 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