dbcve.org
Missing AuthorizationWeakness · CWE-862

CVE-2026-4003

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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 Users manager – PN plugin for WordPress is vulnerable to Privilege Escalation via Arbitrary User Meta Update in all versions up to and including 1.1.15. This is due to a flawed authorization logic check in the userspn_ajax_nopriv_server() function within the 'userspn_form_save' case. The conditional only blocks unauthenticated users when the user_id is empty, but when a non-empty user_id is supplied, execution bypasses this check entirely and proceeds to update arbitrary user meta via update_user_meta() without any authentication or authorization verification. Additionally, the nonce required for this AJAX endpoint ('userspn-nonce') is exposed to all visitors via wp_localize_script on the public wp_enqueue_scripts hook, rendering the nonce check ineffective as a security control. This makes it possible for unauthenticated attackers to update arbitrary user metadata for any user account, including the userspn_secret_token field.

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 Users manager – PN WordPress plugin (versions up to 1.1.15) contains a flawed authorization check in the userspn_ajax_nopriv_server() AJAX function. The code only blocks unauthenticated requests when user_id is empty, but allows execution to proceed when a non-empty user_id is supplied—bypassing all authentication/authorization. Combined with the public exposure of the AJAX nonce via wp_localize_script, unauthenticated attackers can call update_user_meta() to modify arbitrary user metadata for any user account, including privilege-escalation fields like userspn_secret_token.

MitigationUpdate to the latest patched version of the plugin immediately; if no patch exists, disable the plugin and audit user accounts and user_meta tables for unauthorized modifications to privilege-related fields.

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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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 the Users manager - PN plugin is installed
    In the WordPress admin dashboard, navigate to Plugins > Installed Plugins and look for 'Users manager - PN' in the list. Alternatively, check the /wp-content/plugins/ directory for a folder named 'users-manager-pn' or similar.
    Affected if The plugin is installed and active in the WordPress environment
  2. Identify the installed plugin version
    In the WordPress admin, go to Plugins > Installed Plugins and click on the plugin to view its details, or inspect the plugin's main PHP file header for the 'Version' tag. Compare this version to any official security advisories.
    Affected if The installed version has not been patched for this privilege escalation flaw
  3. Confirm the AJAX endpoint is accessible
    Check if the WordPress AJAX endpoint /wp-admin/admin-ajax.php responds to the 'userspn_form_save' action. This can be verified by examining the plugin's JavaScript enqueue or PHP registration for add_action('wp_ajax_userspn_form_save', ...) and add_action('wp_ajax_nopriv_userspn_form_save', ...).
    Affected if The AJAX action 'userspn_form_save' is registered and publicly accessible via admin-ajax.php
  4. Inspect the authorization logic in the AJAX handler
    Locate the function userspn_ajax_nopriv_server() in the plugin's PHP files and examine its conditional logic. Verify whether it properly blocks unauthenticated requests when user_id is provided, or if it allows the request to proceed to update_user_meta().
    Affected if The function fails to enforce authentication when user_id is supplied, allowing unauthenticated metadata updates
  5. Check for nonce exposure via wp_localize_script
    Search the plugin's PHP code for wp_localize_script calls that enqueue the AJAX nonce. Examine the rendered HTML source of any frontend pages loading the plugin's scripts to see if the nonce value is visible in the localized data object.
    Affected if The security nonce is exposed in publicly accessible JavaScript, rendering nonce checks ineffective

The environment is affected if the Users manager - PN plugin is installed with a vulnerable version where the userspn_form_save AJAX endpoint permits unauthenticated user metadata updates.

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 the latest patched version of the plugin immediately; if no patch exists, disable the plugin and audit user accounts and user_meta tables for unauthorized modifications to privilege-related fields.

Recommended fix Moderate confidence

Latest version available on WordPress plugin repository (version higher than 1.1.15)

  1. 1. Navigate to the WordPress admin dashboard and access Plugins > Installed Plugins
  2. 2. Locate the 'Users manager – PN' plugin
  3. 3. Check for available updates - if an update is not visible, manually download the latest version from the WordPress plugin repository at plugins.trac.wordpress.org
  4. 4. Deactivate the current vulnerable version of the plugin
  5. 5. Delete the current plugin files
  6. 6. Upload and install the latest version of the plugin
  7. 7. Reactivate the plugin
  8. 8. Verify that the userspn_ajax_nopriv_server() function has been patched and properly validates authorization before allowing user meta updates

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

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,600
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,160.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-4003 — 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-2026-4003 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