CVE-2026-95866: User Profile Builder <= 4.0.2 - Unauthenticated Stored Cross-Site Scripting via Avatar 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 Avatar Field in all versions up to, and including, 4.0.2 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. The zero-length multipart file branch in wppbsaveavatarvalue() writes the raw request value directly to user meta, bypassing the wppbsaveattachmentid()/wppbverifyattachmentid() validation path; the stored payload is later adopted as a WordPress attachment URL and rendered unescaped by wppbdefaultfieldsmakeuploadbutton() when an administrator views the affected account.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this issue?
WordPress sites using Cozmoslabs User Profile Builder versions 4.0.2 or earlier are affected. Exploitation does not require authentication, and the stored script executes when an administrator views the affected user account.
What does an attacker need to exploit it?
An attacker only needs network access to submit a crafted avatar-field request. The exploit uses the zero-length multipart file handling path to store a raw value in user metadata without the normal attachment-ID validation.
Does exploitation require an administrator to take an action?
Yes. The payload is stored first, then executes when an administrator views the account containing the injected avatar value. No interaction from the attacker with an authenticated session is required.
How can I determine whether my site may be affected?
Check whether the User Profile Builder plugin is installed and whether its version is 4.0.2 or earlier. Review user metadata and affected account avatar values for unexpected or script-like URL content, particularly for accounts created or modified by untrusted users.