Executive brief
Advanced Custom Fields: Extended is a WordPress plugin that allows administrators to create front-end forms for user registration and profile management. The plugin fails to properly restrict user roles submitted through these forms, allowing unauthenticated attackers to register accounts with administrator privileges without authorization. This can lead to complete site compromise and data theft.
Technical details
The vulnerability is a privilege escalation flaw (CWE-269) in the front-end user insertion functionality of Advanced Custom Fields: Extended versions 0.9.2.2 through 0.9.2.6. The plugin does not adequately validate or restrict the role parameter submitted through user registration forms, and safeguards intended to block assignment of privileged roles are incomplete. An unauthenticated attacker can directly submit a request to the vulnerable user form with an elevated role (such as administrator) and bypass the insufficient validation, gaining immediate administrative access to the WordPress installation. The fix is available in version 0.9.2.7 and later.
Affected products
- Advanced Custom Fields Advanced Custom Fields: Extended 0.9.2.2 through 0.9.2.6
Timeline
- 2026-08-31: disclosed
- 2026-09-02: patched: Fixed in version 0.9.2.7