dbcve.org
Unrestricted File UploadWeakness · CWE-434

CVE-2026-6518

HIGH · 8.8 CVSS v3.1 Published 2026-04-18
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 CMP – Coming Soon & Maintenance Plugin by NiteoThemes plugin for WordPress is vulnerable to arbitrary file upload and remote code execution in all versions up to, and including, 4.1.16 via the `cmp_theme_update_install` AJAX action. This is due to the function only checking for the `publish_pages` capability (available to Editors and above) instead of `manage_options` (Administrators only), combined with a lack of proper validation on the user-supplied file URL and no verification of the downloaded file's content before extraction. This makes it possible for authenticated attackers, with Administrator-level access and above, to force the server to download and extract a malicious ZIP file from a remote attacker-controlled URL into a web-accessible directory (`wp-content/plugins/cmp-premium-themes/`), resulting in remote code execution. Due to the lack of a nonce for Editors, they are unable to exploit this vulnerability.

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 CMP Coming Soon & Maintenance plugin for WordPress contains an arbitrary file upload and RCE vulnerability in the `cmp_theme_update_install` AJAX action. Authenticated administrators can supply a remote URL causing the server to download and extract a ZIP file into a web-accessible directory without validating file contents, enabling remote code execution.

MitigationUpdate to version 4.1.17 or later. Until then, restrict access to the affected AJAX action to administrator-level users only and consider disabling the plugin if not needed.

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. Verify CMP plugin is installed
    Log in to WordPress admin and navigate to Plugins > Installed Plugins. Look for 'CMP Coming Soon & Maintenance' in the list, or check the /wp-content/plugins/ directory for a folder starting with 'cmp-' or 'coming-soon-maintenance'.
    Affected if The CMP Coming Soon & Maintenance plugin is not found in the WordPress installation.
  2. Check installed plugin version
    In WordPress admin > Plugins, find the CMP plugin and view the version number displayed below the plugin name. Alternatively, inspect the main plugin PHP file (usually cmp.php or similar in the plugin folder) and look for the 'Version' header in the plugin comments.
    Affected if The installed version is lower than 4.1.17 (the fixed version).
  3. Confirm AJAX action is accessible
    Send a request to /wp-admin/admin-ajax.php with parameter action=cmp_theme_update_install. For unauthenticated or non-admin users, test if the server responds (rather than returning 403 or requiring login). Check the HTTP response code and any error messages.
    Affected if The AJAX endpoint responds to requests without proper admin authentication validation.
  4. Verify administrator-only access to update functions
    Review the plugin source code in the AJAX handler for cmp_theme_update_install. Check if the code properly validates user capabilities using current_user_can() or similar WordPress permission checks before processing the remote URL and extracting files.
    Affected if The AJAX action lacks capability checks or allows execution by users below administrator level.

You are affected if the CMP Coming Soon & Maintenance plugin is installed AND the version is below 4.1.17 AND the vulnerable cmp_theme_update_install AJAX action is accessible without proper admin-only validation.

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 to version 4.1.17 or later. Until then, restrict access to the affected AJAX action to administrator-level users only and consider disabling the plugin if not needed.

Recommended fix Moderate confidence

CMP – Coming Soon & Maintenance Plugin version 4.1.17 or later

  1. Log in to the WordPress admin dashboard
  2. Navigate to Plugins > Installed Plugins
  3. Locate the 'CMP – Coming Soon & Maintenance' plugin by NiteoThemes
  4. If an update is available, click 'Update Now' to upgrade to the latest version
  5. Alternatively, download the latest version from the WordPress Plugin Repository and upload it manually via Plugins > Add New > Upload Plugin
  6. After updating, verify the plugin version is 4.1.17 or higher under Plugins > Installed Plugins

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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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-2026-6518 in production — separate from our analysis above.

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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
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