dbcve.org
Unrestricted File UploadWeakness · CWE-434

CVE-2025-12846

HIGH · 8.8 CVSS v3.1 Published 2025-11-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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
The Blocksy Companion plugin for WordPress is vulnerable to authenticated arbitrary file upload in all versions up to, and including, 2.1.19. This is due to insufficient file type validation detecting SVG files, allowing double extension files to bypass sanitization while being accepted as a valid SVG file. This makes it possible for authenticated attackers, with author level access and above, to upload arbitrary files on the affected site's server which may make remote code execution possible.

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

The Blocksy Companion WordPress plugin fails to properly validate file types during upload, allowing attackers with author-level access to upload arbitrary files via double extensions (e.g., malicious.php.svg) that bypass sanitization while being accepted as valid SVG files, enabling potential remote code execution.

MitigationUpdate Blocksy Companion to version 2.1.20 or later which contains proper file type validation; alternatively, restrict file upload capabilities for author-level users until the patch is applied.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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 Blocksy Companion installation and version
    In WordPress admin, go to Plugins > Installed Plugins and locate Blocksy Companion. Note the version number displayed. Alternatively, check the plugin files in wp-content/plugins/blocksy-companion/ for a version indicator in the main PHP file or readme.txt
    Affected if The installed version is lower than 2.1.20
  2. Verify author-level user upload permissions
    Navigate to WordPress Users > All Users and check which roles have upload_file capability. Authors by default can upload files; confirm if any custom roles or permissions grant upload access to author-level accounts
    Affected if Author-level users or any user with upload_file capability can access the upload functionality
  3. Confirm SVG upload functionality is active
    Check WordPress Media Library settings or use a plugin scanner to determine if SVG file uploads are permitted. Inspect the media settings at Settings > Media to see if SVGs are being processed
    Affected if SVG files can be uploaded and are not being blocked or sanitized before storage
  4. Inspect uploaded file storage location
    Examine the wp-content/uploads/ directory for any recently uploaded .svg files. Check if double-extension files (e.g., file.php.svg) exist in the uploads folder
    Affected if SVG files with double extensions or files that are actually PHP scripts masquerading as SVG files are present in the uploads directory

The environment is affected if Blocksy Companion version is below 2.1.20 AND author-level users can upload files AND SVG uploads are enabled, allowing potential execution of uploaded malicious files.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Blocksy Companion to version 2.1.20 or later which contains proper file type validation; alternatively, restrict file upload capabilities for author-level users until the patch is applied.

Recommended fix Moderate confidence

Blocksy Companion version 2.1.20 or later

  1. Log in to the WordPress admin dashboard
  2. Navigate to Plugins > Installed Plugins
  3. Locate the Blocksy Companion plugin
  4. Check if an update to version 2.1.20 or later is available
  5. If an update is available, click 'Update Now' to install the patched version
  6. If no automatic update is available, manually download version 2.1.20 or later from the WordPress plugin repository and upload via Plugins > Add New > Upload Plugin
  7. After updating, verify the new version is installed under Plugins > Installed Plugins
  8. Consider reviewing uploaded files in the media library to ensure no malicious files were uploaded prior to the patch

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-12846 — 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-2025-12846 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