Formidable Forms <= 6.28 - Missing Authorization to Unauthenticated Payment Integrity Bypass via PaymentIntent Reuse
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-862.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| strategy11team | Formidable Forms – Contact Form Plugin, Survey, Quiz, Payment, Calculator Form & Custom Form Builder | up to 6.28 | — | No fix listed | CNA |
- Formidable Forms – Contact Form Plugin, Survey, Quiz, Payment, Calculator Form & Custom Form Builder Vendorstrategy11team Affected up to 6.28 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-2890
- 2026-10-03 Alias added: GHSA-4rrh-wqqx-4jh2
References
Other 4
- 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
More strategy11team vulnerabilities
- TI-2022-03006 AWP Classifieds Plugin < 4.3 - Unauthenticated SQLi CVSS 3.1CRITICAL 9.8
- TI-2023-02696 Formidable Forms < 6.3.1 - Subscriber+ Remote Code Execution CVSS 3.1HIGH 8.8
- TI-2023-01329 Formidable Forms < 6.2 - Unauthenticated PHP Object Injection CVSS 3.1HIGH 7.5
- TI-2023-00774 Formidable Forms < 6.1 - IP Spoofing CVSS 3.1MEDIUM 6.5
- TI-2024-09065 Formidable Forms < 6.14.1 - Admin+ Stored XSS CVSS 3.1MEDIUM 4.8
- TI-2024-04133 SQL injection in strategy11team Business Directory Plugin – Easy Listing Directories for… CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-2890 · CVE Program
- CVE-2026-2890 · NVD
- FIRST EPSS
- GHSA-4rrh-wqqx-4jh2 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences