CVE-2026-15826
CriticalExploitedThe User Profile Builder plugin for WordPress is vulnerable to Authentication Bypass via Type Confusion in versions up to, and including, 3.16.4.
Published Aug 15, 2026 · Updated Aug 20, 2026 · Also known as 9f606fba-f779-42ea-a160-6c3b20dc5e79
Key Facts
Patch immediately- CVE-2026-15826 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting profile-builder (wordpress-plugin), User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor.
- It is exploited in the wild, listed in Industry KEV feed since Aug 15, 2026. No public exploit code is known.
- EPSS estimates a 3.9% probability of exploitation in the next 30 days.
- Fixed versions are available, including profile-builder 3.16.5.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
3.9%
Higher than 90.1% of all scored CVEs
Exploited in the wild
Yes
1 catalog listing
Public exploit code
None known
Get the full CVE-2026-15826 brief as a PDF
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Aug 15, 2026 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| profile-builderwordpress-plugin | See advisory | 3.16.5 |
| User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor | See advisory | n/a |
Patched Releases
profile-builder
3.16.5
Timeline
Publicly disclosed
Aug 15, 2026
Added to Industry KEV feed
Aug 15, 2026
Last updated
Aug 20, 2026
Weakness Type
- CWE-704 Incorrect Type Conversion or Cast
References
- advisoryhttps://plugins.trac.wordpress.org/browser/wholesale-market/tags/2.2.2/addons/wholesale-request/include/class-wholesale-user-register-addon.php#L141
- advisoryhttps://plugins.trac.wordpress.org/browser/wholesale-market/tags/2.2.2/addons/wholesale-request/include/class-wholesale-user-register-addon.php#L153
- advisoryhttps://plugins.trac.wordpress.org/browser/wholesale-market/tags/2.2.2/addons/wholesale-request/include/class-wholesale-user-register-addon.php#L276
- advisoryhttps://plugins.trac.wordpress.org/browser/wholesale-market/tags/2.2.2/addons/wholesale-request/include/class-wholesale-user-register-addon.php#L30
- advisoryUSOM advisory
FAQ
Common Questions.
The User Profile Builder plugin for WordPress is vulnerable to Authentication Bypass via Type Confusion in versions up to, and including, 3.16.4.
Affected: profile-builder (wordpress-plugin); User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Aug 15, 2026.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including profile-builder 3.16.5.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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