CVE-2026-15826 Auth bypass in User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor
Unauthenticated attackers can bypass authentication via type confusion to gain administrator access and take over the WordPress site.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-15826?
CVE-2026-15826 is a critical authentication bypass vulnerability in cozmoslabs User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-704
Which versions are affected by CVE-2026-15826?
How do I fix CVE-2026-15826?
No fix has been published for CVE-2026-15826 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-15826 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-15826 exists.
Public exploit code: 1 Nuclei template and 1 proofs of concept on GitHub.
Sources
Also known as GHSA-2v77-3rr8-9p3p.