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.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 29 May 2026 16:00:00 +0000

Type Values Removed Values Added
First Time appeared Scottpaterson
Scottpaterson contact Form 7 – Paypal & Stripe Add-on
Wordpress
Wordpress wordpress
Vendors & Products Scottpaterson
Scottpaterson contact Form 7 – Paypal & Stripe Add-on
Wordpress
Wordpress wordpress

Fri, 29 May 2026 10:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 29 May 2026 09:00:00 +0000

Type Values Removed Values Added
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.
Title Contact Form 7 – PayPal & Stripe Add-on <= 2.4.9 - Unauthenticated Payment Bypass via Insufficient Verification of Data Authenticity via PayPal IPN Handler ('invoice'/'mc_gross' Verification)
Weaknesses CWE-345
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: Wordfence

Published:

Updated: 2026-05-29T10:04:53.551Z

Reserved: 2026-05-21T15:06:53.761Z

Link: CVE-2026-9189

cve-icon Vulnrichment

Updated: 2026-05-29T10:04:47.955Z

cve-icon NVD

Status : Deferred

Published: 2026-05-29T09:16:18.560

Modified: 2026-05-29T13:09:05.450

Link: CVE-2026-9189

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-29T15:47:21Z

Weaknesses