Executive brief
Fluent Forms is a popular WordPress plugin used to create forms and manage customer payments and subscriptions. A security flaw allows any logged-in user, such as a basic subscriber, to cancel the active subscriptions of other customers. This could lead to unexpected service disruptions for customers and loss of recurring revenue for the business.
Technical details
An Insecure Direct Object Reference (IDOR) vulnerability exists in the Fluent Forms plugin due to insufficient authorization checks in the 'cancel_transaction' route of the 'fluentform_user_payment_endpoints' AJAX action. While the plugin requires a valid nonce, it fails to verify that the 'subscription_id' provided in the POST request belongs to the currently authenticated user. An attacker with a low-privilege Subscriber account and their own active subscription can obtain a valid nonce and then submit a request to cancel any other user's subscription by providing the victim's ID. This issue is fixed in version 6.2.1.
Affected products
- WPManageNinja Fluent Forms before 6.2.1
Timeline
- 2026-06-10: disclosed
- 2026-06-10: advisory
- 2026-07-01: other: NVD publication date