FKIE_CVE-2026-9189

Vulnerability from fkie_nvd - Published: 2026-05-29 09:16 - Updated: 2026-05-29 13:09
Severity
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
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.
References
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/functions.php#L31
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/paypal_handler.php#L106
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/paypal_handler.php#L75
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/functions.php#L31
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/paypal_handler.php#L106
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/paypal_handler.php#L75
security@wordfence.comhttps://plugins.trac.wordpress.org/changeset/3551197/contact-form-7-paypal-add-on
security@wordfence.comhttps://www.wordfence.com/threat-intel/vulnerabilities/id/5e274781-1c20-4224-bc10-26dadb9b1e07?source=cve
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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": "CVE-2026-9189",
  "lastModified": "2026-05-29T13:09:05.450",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "security@wordfence.com",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-05-29T09:16:18.560",
  "references": [
    {
      "source": "security@wordfence.com",
      "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",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/paypal_handler.php#L106"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/paypal_handler.php#L75"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/functions.php#L31"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/paypal_handler.php#L106"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/paypal_handler.php#L75"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/changeset/3551197/contact-form-7-paypal-add-on"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/5e274781-1c20-4224-bc10-26dadb9b1e07?source=cve"
    }
  ],
  "sourceIdentifier": "security@wordfence.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-345"
        }
      ],
      "source": "security@wordfence.com",
      "type": "Primary"
    }
  ]
}


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