What the vulnerability does
01Description
The Formidable Forms plugin for WordPress is vulnerable to a payment integrity bypass in all versions up to, and including, 6.28. This is due to the Stripe Link return handler (`handle_one_time_stripe_link_return_url`) marking payment records as complete based solely on the Stripe PaymentIntent status without comparing the intent's charged amount against the expected payment amount, and the `verify_intent()` function validating only client secret ownership without binding intents to specific forms or actions. This makes it possible for unauthenticated attackers to reuse a PaymentIntent from a completed low-value payment to mark a high-value payment as complete, effectively bypassing payment for goods or services.
Explanation of Vulnerability in Simple Terms
02Summary
Formidable Forms versions 6.28 and earlier lack proper authorization checks, allowing unauthenticated attackers to modify form data or settings over the network. No user interaction is required. The vulnerability affects the integrity of form submissions and configurations but does not expose sensitive data or cause service disruption.
What an attacker can do
03Attacker Capabilities
Modify form data, settings, or submissions without logging in.
Potential impact on your site
04Site Impact
Form submissions and configurations can be altered by anyone, compromising data integrity and form functionality.
Conditions required to exploit
05Prerequisites
Network access to the site; no authentication or user interaction required.
Key dates
06Disclosure timeline
March 13, 2026
CVE published
April 8, 2026
Record updated
