User Profile Builder <= 3.16.4 - Unauthenticated Authentication Bypass via Type Confusion to Administrator Account Takeover via 'username' Parameter
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor | <= 3.16.4 | 3.16.5 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-704- Platform
- WordPress
- Package
User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor- Disclosed
- 14.08.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
Wordfence Intelligence - 9f606fba-f779-42ea-a160-6c3b20dc5e79 - Wordfence Intelligence
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Copyright 2012-2026 Defiant Inc.
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Vulnerability history: User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 46
- First → latest
- 05.2014 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 7
- High 9
- Medium 30
Disclosures per year
- 2017: 1
- 2018: 0
- 2019: 0
- 2020: 2
- 2021: 2
- 2022: 3
- 2023: 4
- 2024: 6
- 2025: 6
- 2026: 15
earlier: 7
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User Profile Builder <= 3.16.4 - Unauthenticated Authentication Bypass via Type Confusion to Administrator Account Takeover via 'username' Parameter this entry
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