Insufficient verification of data authenticity in Scott Paterson Contact Form 7 – PayPal…
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-345.
Summary
The Contact Form 7 – PayPal & Stripe Add-on plugin for WordPress is vulnerable to Payment Bypass via Insufficient Verification of Data Authenticity in all versions up to, and including, 2.4.9. Although `cf7pp_paypal_ipn_handler()` correctly validates IPN authenticity by posting back to PayPal with `cmd=_notify-validate`, it fails to compare the IPN payload's `mc_gross` (payment amount), `mc_currency`, or `receiver_email` fields against the corresponding stored order values before passing the attacker-controlled `invoice` field directly to `cf7pp_complete_payment()`, which marks the order completed after only an integer cast with no amount verification. This makes it possible for unauthenticated attackers to mark arbitrary high-value pending orders as fully paid by making a minimal real PayPal payment and crafting an IPN whose `invoice` parameter references the targeted order, effectively completing purchases without tendering the required payment amount.
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 |
|---|---|---|---|---|---|
| Scott Paterson | Contact Form 7 – PayPal & Stripe Add-on | up to 2.4.9 | — | No fix listed | CNA |
- Contact Form 7 – PayPal & Stripe Add-on VendorScott Paterson Affected up to 2.4.9 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-9189
- 2026-10-03 Alias added: GHSA-vr4h-g9wj-2p4g
References
Other 8
- https://www.wordfence.com/threat-intel/vulnerabilities/id/5e274781-1c20-4224-bc10-26dadb9b1e07?source=cve
- https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/paypal_handler.php#L106
- https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/paypal_handler.php#L75
- https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/functions.php#L31
- https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/paypal_handler.php#L106
- https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/paypal_handler.php#L75
- https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/functions.php#L31
- https://plugins.trac.wordpress.org/changeset/3551197/contact-form-7-paypal-add-on
More Scott Paterson vulnerabilities
- TI-2024-33923 WordPress ScottCart plugin <= 1.1 - Remote Code Execution (RCE) vulnerability CVSS 3.1CRITICAL 9.8
- TI-2026-25298 Easy PayPal Events & Tickets < 1.4 Authentication Bypass via QR Code Scanning CVSS 4.0HIGH 8.7
- TI-2026-30060 Easy PayPal Events & Tickets < 1.4 Information Disclosure via QR Code Endpoint CVSS 4.0HIGH 8.2
- TI-2022-04229 Easy PayPal Buy Now Button < 1.7.4 - Contributor+ Stored XSS in Shortcode CVSS 3.1MEDIUM 5.4
- TI-2024-08900 Time Clock <= 1.2.2 & Time Clock Pro <= 1.1.4 - Unauthenticated (Limited) Remote Code Execution CVSS 3.1HIGH 8.3
- TI-2025-31350 WordPress Easy Stripe plugin <= 1.1 - Remote Code Execution (RCE) Vulnerability CVSS 3.1CRITICAL 10.0
Sources
- CVE-2026-9189 · CVE Program
- CVE-2026-9189 · NVD
- FIRST EPSS
- GHSA-vr4h-g9wj-2p4g · 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