CVE-2026-100186: User Profile Builder <= 4.0.3 - Unauthenticated Stored Cross-Site Scripting via First Name Field
The User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via First Name Field in all versions up to, and including, 4.0.3 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This vulnerability is only exploitable when the Email Confirmation feature is enabled in Profile Builder.
Affected Software
Event History
Frequently Asked Questions
Which installations are exposed to exploitation?
Installations running User Profile Builder version 4.0.3 or earlier are affected only if the plugin's Email Confirmation feature is enabled. The issue is reachable remotely without authentication or user interaction from the attacker.
What is the practical impact of a successful attack?
An attacker can place arbitrary web script in the First Name field, where it is stored and later executes when a user accesses an affected page. The supplied severity vector indicates potential impact to confidentiality and integrity, with scope changed.
How can I determine whether my site is at risk?
Check whether Cozmoslabs User Profile Builder is installed at version 4.0.3 or earlier, and verify whether its Email Confirmation feature is enabled. Both conditions must be present for this vulnerability to be exploitable.