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)
CVE-2026-9189Published · Updated Action summary
Affected: ≤2.4.9Update to 2.4.10 or newer
All remediation steps- Severity
- Medium5.3
- CVSS
- 5.3CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NWhat does this vector mean?
AV:NAttack vector- Network
AC:LAttack complexity- Low
PR:NPrivileges required- None
UI:NUser interaction- None
S:UScope- Unchanged
C:NConfidentiality- None
I:LIntegrity- Low
A:NAvailability- None
- Required access
- No account needed
- Exploit prediction (EPSS)
- No score
- CISA KEV
- Not listed
On this page8
Am I affected?
Contact Form 7 – PayPal & Stripe Add-on contact-form-7-paypal-add-on
- Affected≤ 2.4.9
- Patched in2.4.10
Update to 2.4.10 or newer.
You are affected if you run ≤ 2.4.9. Version 2.4.10 and later are not affected by this issue.
- Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Contact Form 7 – PayPal & Stripe Add-on.
- No admin access? Run a passive check of your site. It reads public files only.
- No account is needed to exploit this. Treat any exposed site on an affected version as at risk.
What to do
- Update to version 2.4.10, or a newer patched version
- Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
- Watch Contact Form 7 – PayPal & Stripe Add-on to get an email when the next vulnerability is published.
Advisory
Source description from Wordfence Intelligence, credited to Muni Nitish Kumar Yaddala (Stranger825).
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.
Exploits & references
Proof-of-concept & detection
No public proof-of-concept or detection template is known for this vulnerability.
Advisories & patches
- Advisorywordfence.com
Related CVEs
More in Contact Form 7 – PayPal & Stripe Add-on
All 9| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| Medium5.3 | Missing Authorization ≤2.5.1Update to 2.5.2 | CVE-2026-66660 | |
| Medium5.8 | Open Redirect ≤2.4Update to 2.5 | CVE-2026-14236 | |
| Medium4.4 | Authenticated (Administrator+) Stored Cross-Site Scripting ≤2.3.4Update to 2.4.1 | CVE-2025-47518 | |
| Medium6.1 | PayPal & Stripe Add-on <= 2.3.1 - Reflected Cross-Site Scripting ≤2.3.1Update to 2.3.2 | CVE-2024-10683 | |
| Medium6.1 | Reflected Cross-Site Scripting ≤2.3Update to 2.3.1 | CVE-2024-48021 |
- Medium5.3Missing Authorization
≤2.5.1Update to 2.5.2
- Medium5.8Open Redirect
≤2.4Update to 2.5
- Medium4.4Authenticated (Administrator+) Stored Cross-Site Scripting
≤2.3.4Update to 2.4.1
- Medium6.1PayPal & Stripe Add-on <= 2.3.1 - Reflected Cross-Site Scripting
≤2.3.1Update to 2.3.2
- Medium6.1Reflected Cross-Site Scripting
≤2.3Update to 2.3.1
Timeline
CVE published
Severity medium, CVSS 5.3
Record last updated
Sources & licenses
Wordfence record- Vulnerability data
- Wordfence Intelligence. Copyright 2012-2026 Defiant Inc. Licensed under the CC BY-SA 4.0.
- CVE® identifiers
- Copyright 1999-2026 The MITRE Corporation. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
- CVSS / CWE
- National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
- VulnCrest content
- Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.