User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor < 4.0.1 - Authenticated (Administrator+) PHP Object Injection
Strategic Overview
- Status
- Patched in 4.0.1
- Affected Plugin
- User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor
- Affected Version
< 4.0.1- CVSS
- 6.6Medium
- Weakness type
- CWE-502 · Deserialization of Untrusted Data
- CVE
CVE-2026-76547
At a glance
CVE-2026-76547 is a medium-severity Deserialization of Untrusted Data vulnerability in the User Profile Builder WordPress plugin, affecting versions < 4.0.1. It carries a CVSS score of 6.6 (reachable over the network; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Administrator level or above. The issue is fixed in version 4.0.1; sites on affected versions should update now. Disclosed August 2026, reported by Vivien LEBAS.
Vulnerability Overview
The User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor plugin for WordPress is vulnerable to PHP Object Injection in all versions up to 4.0.1. This is due to deserialization of untrusted input. This makes it possible for authenticated attackers, with administrator-level access and above, to inject a PHP Object. No known POP chain is present in the vulnerable software. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.
CWE-502: Deserialization of Untrusted Data
Reaching this weakness in User Profile Builder < 4.0.1 takes an account at Administrator level or above. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.
A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For User Profile Builder the fix is 4.0.1: builds < 4.0.1 are affected, anything from 4.0.1 onward is not.
Remediation
Update to version 4.0.1, or a newer patched version
How does WordSec protect against this?
An attacker needs Administrator access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: User Profile Builder 4.0.1 closes this, and updating the plugin is the step that ends it.
- Firewall
- Scanner
- Alerts
External References
Related records
Other vulnerabilities in User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor
- 9.8CVE-2026-15826: User Profile Builder <= 3.16.4 Authentication Bypass
CVE-2026-15826 - 9.8CVE-2025-15030: User Profile Builder <= 3.15.1 Privilege Escalation
CVE-2025-15030 - 9.8CVE-2024-6695: User Profile Builder Authentication Bypass
CVE-2024-6695 - 9.8CVE-2023-2297: Profile Builder Insecure Password Reset Mechanism
CVE-2023-2297 - 9.8CVE-2021-24527: Profile Builder <= 3.4.8 Admin Access
CVE-2021-24527 - 9.8Profile Builder <= 3.1.0 Privilege Escalation
- 9.8Profile Builder Authentication Bypass
- 8.8CVE-2021-36915: Profile Builder CSRF
CVE-2021-36915
Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C