CVE-2026-4003 Privilege escalation in Users manager – PN
Unauthenticated attackers can escalate privileges and take over accounts by updating arbitrary user metadata due to flawed authorization checks in the Users manager – PN plugin.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-4003?
CVE-2026-4003 is a critical vulnerability in felixmartinez Users manager – PN, published on 8 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-862
Which versions are affected by CVE-2026-4003?
How do I fix CVE-2026-4003?
No fix has been published for CVE-2026-4003 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-4003 being exploited?
There is no known exploitation of CVE-2026-4003 in the wild and no public exploit code.
Sources
Also known as GHSA-f474-j5g7-2pch.