User Profile Builder registration can log visitors in as existing Administrators
User Profile Builder before 3.16.4 does not correctly bind its automatic post-registration login to the account that was just created. On sites using a supported but non-default configuration, an unauthenticated visitor can manipulate the registration flow and receive an authenticated session for an arbitrary existing user, including an Administrator. The published record does not disclose the required configuration, registration endpoint or fields, session-binding function or exact account selector.
- Component
- User Profile Builder
- Plugin slug
user-profile-builder- Affected
- < 3.16.4
- Safe version
3.16.4- Published
- Aug 01, 2026
- Weakness
- Not assigned
This CVE was published Aug 01, 2026 and is one of 2 known issues for this plugin.
Update, patch or deactivate.
Update User Profile Builder to 3.16.4 or later. Review the plugin's automatic-login configuration, recent registrations and sessions that unexpectedly became established users, invalidate suspicious sessions, reset affected credentials, and investigate administrator activity if takeover may have occurred.
A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.
Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.
Technical description
The User Profile Builder WordPress plugin before 3.16.4 does not correctly bind the automatic login performed after user registration to the newly created account, allowing unauthenticated attackers to obtain an authenticated session for an arbitrary existing user, including administrators, on sites using a supported but non-default configuration.