User Profile Builder <= 3.16.4 - Unauthenticated Authentication Bypass via Type Confusion to Administrator Account Takeover via 'username' Parameter
Summary
| CVE | CVE-2026-15826 |
|---|---|
| State | PUBLISHED |
| Assigner | Wordfence |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-15 07:16:19 UTC |
| Updated | 2026-08-15 07:16:19 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 9.8 CRITICAL from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Problem Types: CWE-704 | CWE-704 CWE-704 Incorrect Type Conversion or Cast
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Cozmoslabs | User Profile Builder Beautiful User Registration Forms User Profiles User Role Editor | affected 3.16.4 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| plugins.trac.wordpress.org/browser/profile-builder/tags/3.16.4/features/functions.php | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/profile-builder/tags/3.16.4/front-end/class-formbuild... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/profile-builder/tags/3.16.4/front-end/default-fields/... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/profile-builder/tags/3.16.4/front-end/class-formbuild... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/profile-builder/tags/3.16.4/front-end/default-fields/... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/profile-builder/tags/3.16.4/front-end/class-formbuild... | [email protected] | plugins.trac.wordpress.org | |
| www.wordfence.com/threat-intel/vulnerabilities/id/9f606fba-f779-42ea-a160-6c3b2... | [email protected] | www.wordfence.com | |
| plugins.trac.wordpress.org/changeset/3609855/profile-builder | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/profile-builder/tags/3.16.4/front-end/class-formbuild... | [email protected] | plugins.trac.wordpress.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Supakiad S. (m3ez) (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-07-15T14:14:08.000Z | Vendor Notified |
| CNA | 2026-08-14T18:24:03.000Z | Disclosed |
There are currently no legacy QID mappings associated with this CVE.