Executive brief
The User Registration & Membership plugin for WordPress, which manages user sign-ups and paid subscriptions, contains a flaw that allows users to bypass payment requirements. An attacker can register for a new account and then manipulate the registration process to activate a premium, paid membership plan without actually paying. This results in unauthorized access to restricted content and a loss of subscription revenue for the site owner.
Technical details
An authentication bypass vulnerability exists in the User Registration & Membership plugin (versions prior to 5.2.0) due to insufficient validation in the membership registration logic. Specifically, the `user_registration_membership_register_member` AJAX action does not properly enforce payment verification when a `payment_method` of 'free' is manually supplied for a paid plan. An unauthenticated attacker can first self-register a standard account and then send a crafted POST request to `admin-ajax.php` using a valid frontend nonce to activate any paid membership plan. This results in an 'active' status in the membership subscriptions table without a corresponding transaction, granting access to gated content.
Affected products
- WPEverest User Registration & Membership < 5.2.0
Timeline
- 2026-06-11: disclosed: Publicly published by WPScan
- 2026-07-02: advisory: NVD published date