GHSA-VR4H-G9WJ-2P4G

Vulnerability from github – Published: 2026-05-29 09:31 – Updated: 2026-05-29 09:31
VLAI
Details

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.

Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2026-9189"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-345"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-29T09:16:18Z",
    "severity": "MODERATE"
  },
  "details": "The Contact Form 7 \u2013 PayPal \u0026 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\u0027s `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.",
  "id": "GHSA-vr4h-g9wj-2p4g",
  "modified": "2026-05-29T09:31:07Z",
  "published": "2026-05-29T09:31:07Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9189"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/functions.php#L31"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/paypal_handler.php#L106"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/paypal_handler.php#L75"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/functions.php#L31"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/paypal_handler.php#L106"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/paypal_handler.php#L75"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/changeset/3551197/contact-form-7-paypal-add-on"
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/5e274781-1c20-4224-bc10-26dadb9b1e07?source=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}


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