Formidable Forms <= 6.28 - Missing Authorization to Unauthenticated Payment Integrity Bypass via PaymentIntent Reuse
Published Mar 13, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
Formidable Forms <= 6.28 - Missing Authorization to Unauthenticated Payment Integrity Bypass via PaymentIntent Reuse
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
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.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- www.wordfence.com ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
Record history
Published Mar 13, 2026 · Last refreshed Nov 3, 2026