What the vulnerability does
01Description
The MetForm Pro plugin for WordPress is vulnerable to Improper Input Validation in all versions up to, and including, 3.9.7 This is due to the payment integrations (Stripe/PayPal) trusting a user-submitted calculation field value without recomputing or validating it against the configured form price. This makes it possible for unauthenticated attackers to manipulate the payment amount via the 'mf-calculation' field in the form submission REST request granted there exists a specific form with this particular configuration.
Explanation of Vulnerability in Simple Terms
02Summary
MetForm Pro versions up to 3.9.7 contain an input validation flaw that allows attackers to modify data without authentication. The vulnerability requires only network access and no user interaction. Site administrators should update to a version newer than 3.9.7 to prevent unauthorized data tampering.
What an attacker can do
03Attacker Capabilities
Modify or tamper with form data or site content without logging in.
Potential impact on your site
04Site Impact
Attackers can alter form submissions, user data, or other site content without permission.
Conditions required to exploit
05Prerequisites
Network access only; no authentication or user interaction required.
Key dates
06Disclosure timeline
April 15, 2026
CVE published
April 15, 2026
Record updated
