CVE-2026-9189
Vulnérabilité moyenne dans Contact Form 7 – PayPal & Stripe Add-on (scottpaterson)
Description
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.
Gravité et risque d'exploitation
CVE-2026-9189 obtient un score CVSS de 5.3/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.25 %, ce qui la place devant 15.1 % des CVE référencées.
Que faire ?
- Vérifiez si Contact Form 7 – PayPal & Stripe Add-on (versions 0, <=2.4.9) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- 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
