CVE-2026-9189
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.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- Puntuación base: 5.3
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.25%
- Percentil entre todas las CVEs puntuadas: 15
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-345
Referencias
- 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/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/2.4.8/includes/payments/functions.php#L31
- 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/changeset/3551197/contact-form-7-paypal-add-on
- https://www.wordfence.com/threat-intel/vulnerabilities/id/5e274781-1c20-4224-bc10-26dadb9b1e07?source=cve
JSON original (NVD)
Mostrar
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"id": "CVE-2026-9189",
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{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-9189",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-05-29T10:00:42.885449Z"
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"integrityImpact": "LOW",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 1.4,
"exploitabilityScore": 3.9
}
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"affected": [
{
"source": "security@wordfence.com",
"affectedData": [
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"vendor": "scottpaterson",
"product": "Contact Form 7 – PayPal & Stripe Add-on",
"versions": [
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"status": "affected",
"version": "0",
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"lessThanOrEqual": "2.4.9"
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"defaultStatus": "unaffected"
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"published": "2026-05-29T09:16:18.560",
"references": [
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"url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/functions.php#L31",
"source": "security@wordfence.com"
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"source": "security@wordfence.com"
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{
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"source": "security@wordfence.com"
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"description": [
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"value": "CWE-345"
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"descriptions": [
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"lang": "en",
"value": "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."
},
{
"lang": "es",
"value": "El plugin Contact Form 7 – PayPal & Stripe Add-on para WordPress es vulnerable a una Omisión de Pago (Payment Bypass) a través de una Verificación Insuficiente de la Autenticidad de los Datos en todas las versiones hasta la 2.4.9, inclusive. Aunque `cf7pp_paypal_ipn_handler()` valida correctamente la autenticidad del IPN al enviar una publicación de vuelta a PayPal con `cmd=_notify-validate`, no compara los campos `mc_gross` (importe del pago), `mc_currency` o `receiver_email` del payload del IPN con los valores de pedido almacenados correspondientes antes de pasar el campo `invoice` controlado por el atacante directamente a `cf7pp_complete_payment()`, el cual marca el pedido como completado después de solo una conversión a entero sin verificación de importe. Esto hace posible que atacantes no autenticados marquen pedidos pendientes arbitrarios de alto valor como totalmente pagados al realizar un pago real mínimo de PayPal y elaborar un IPN cuyo parámetro `invoice` haga referencia al pedido objetivo, completando efectivamente las compras sin abonar el importe de pago requerido."
}
],
"lastModified": "2026-07-21T12:10:00.090",
"sourceIdentifier": "security@wordfence.com"
}