Unrestricted File UploadWeakness · CWE-434

CVE-2026-28133

HIGH · 8.5 CVSS v3.1 Published 2026-03-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
91/100
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
Unrestricted Upload of File with Dangerous Type vulnerability in WP Chill Filr filr-protection allows Upload a Web Shell to a Web Server.This issue affects Filr: from n/a through <= 1.2.14.

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 WP Chill Filr plugin has an unrestricted file upload vulnerability allowing attackers to upload dangerous file types (including web shells) directly to the web server. This enables remote code execution since uploaded PHP files can be executed by the web server.

MitigationUpdate the Filr plugin to the latest patched version. If no patch is available, disable the plugin immediately and implement server-level restrictions to block execution of uploaded files in the wp-content/uploads directory.

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
High
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/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. Verify Filr plugin is installed
    Check WordPress plugins admin page or inspect wp-content/plugins directory for the filr folder
    Affected if The Filr plugin by WP Chill is present and active in the WordPress installation
  2. Identify the installed Filr plugin version
    Access the plugin via WordPress admin (Plugins > Installed Plugins > Filr) or read the main plugin file header for the Version field
    Affected if The installed version is any version prior to the vendor releasing a security patch for this CVE
  3. Confirm the file upload endpoint exists and is accessible
    Check for the presence of upload-handling scripts in the plugin directory or test accessing common Filr upload routes
    Affected if The plugin exposes any file upload functionality without proper restrictions
  4. Verify uploads directory allows PHP execution
    Check the .htaccess file or server configuration in wp-content/uploads for directives that block PHP execution (such as 'php_flag engine off' or 'deny from all' for PHP files)
    Affected if The uploads directory permits execution of uploaded PHP files (no security restrictions in place)

The environment is affected if the WP Chill Filr plugin is installed and the uploads directory does not block PHP execution, allowing uploaded files to be executed by the web server.

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 the Filr plugin to the latest patched version. If no patch is available, disable the plugin immediately and implement server-level restrictions to block execution of uploaded files in the wp-content/uploads directory.

Recommended fix Moderate confidence

Latest version of Filr plugin (version > 1.2.14)

  1. 1. Update the WP Chill Filr plugin to the latest available version to remediate the unrestricted file upload vulnerability
  2. 2. After updating, verify that file upload functionality is working as expected
  3. 3. Review uploaded files on the server to ensure no malicious files were uploaded during the vulnerable period
  4. 4. Consider implementing additional file upload validation at the server level as a defense-in-depth measure

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

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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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-2026-28133 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