Description

The Formidable Forms WordPress plugin before 6.32.1 does not properly validate the status of a PayPal subscription payment before marking it complete, allowing unauthenticated users to bypass payment and trigger paid form actions — such as digital content access, license delivery, and membership activation — without being charged.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.9",
  "pubDate": "2026-08-06T22:16:44.690Z",
  "pubdate": "2026-08-06T22:16:44.690Z",
  "executiveSummary": "An improper payment validation vulnerability exists in the Formidable Forms WordPress plugin prior to version 6.32.1.\nThe flaw allows unauthenticated remote attackers to bypass the verification mechanism for PayPal subscription payments, leading to unauthorized completion of payment workflows.\nSuccessful exploitation enables malicious actors to trigger downstream paid form actions without rendering any financial transaction, resulting in unauthorized digital content access, automated license key delivery, and unauthorized membership activation.\nThe vulnerability presents a significant business logic risk for site administrators relying on the plugin for monetization, subscriptions, or gated content delivery.\nNo elevated privileges or pre-existing authentication are required to execute the attack, lowering the barrier to entry for malicious actors targeting exposed instances over the network.",
  "technicalDetails": "The root cause of the vulnerability lies in the insufficient server-side validation of incoming payment status notifications or webhooks processed by the Formidable Forms WordPress plugin.\nSpecifically, the vulnerable component fails to adequately verify whether a PayPal subscription payment has successfully cleared and settled before transitioning the internal transaction state to complete.\nThe attack flow begins when an unauthenticated attacker interacts with the payment processing endpoints exposed by the plugin.\nInstead of supplying a legitimate, cryptographically verified payment confirmation or completing the checkout process through the official PayPal gateway, the attacker can manipulate transaction parameters or send crafted requests that mimic a successful payment payload.\nBecause the plugin inadequately validates the authenticity and status flags of the transaction data, it improperly trusts the unverified input.\nConsequently, the application treats the fraudulent request as a valid, completed payment event.\nThis triggers the execution of post-payment actions configured within the specific form, such as granting access to restricted digital assets, generating and dispatching software licenses, or elevating user account roles for membership activation.\nThe affected versions include all instances of the Formidable Forms WordPress plugin predating version 6.32.1.\nNetwork exposure is inherent to any WordPress installation running the vulnerable plugin with active PayPal payment forms accessible via standard HTTP/HTTPS protocols."
}