User Profile Builder <= 3.16.4 - Unauthenticated Authentication Bypass via Type Confusion to Administrator Account Takeover via 'username' Parameter
| CVE | CVE-2026-15826 |
|---|---|
| CVSS | 9.8 (Critical) |
| Publicly Published | August 14, 2026 |
| Last Updated | August 15, 2026 |
| Researcher |
Supakiad S. (m3ez) (m3ez)
- E-CQURITY (Thailand)
|
Description
The User Profile Builder plugin for WordPress is vulnerable to Authentication Bypass via Type Confusion in versions up to, and including, 3.16.4. This is due to the wppb_log_in_user() function calling absint() on the return value of wp_insert_user() before performing an is_wp_error() check — when a registration is submitted with a 61–70 character username, WordPress core rejects it with a WP_Error object, but absint() coerces that object to the integer 1 before the error check can short-circuit execution, causing the plugin to bind and return a transient-backed autologin nonce tied to user ID 1. This makes it possible for unauthenticated attackers to log in as the site's Administrator account (user ID 1), resulting in full administrative takeover of the site.
Wordfence blocked 330 attacks targeting this vulnerability in the past 24 hours.
References
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
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Vulnerability Details for User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor
| Software Type | Plugin |
|---|---|
| Software Slug | profile-builder (view on wordpress.org) |
| Patched? | Yes |
| Remediation | Update to version 3.16.5, or a newer patched version |
| Affected Version |
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| Patched Version |
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Recent vulnerabilities in User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor
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