Vulnerability in Contact Form 7 – PayPal & Stripe Add-on (WordPress plugin) (CVE-2026-9189)
Summary
Vulnerability in Contact Form 7 – PayPal & Stripe Add-on (WordPress plugin) (CVE-2026-9189). Risk of unauthorized operations or information disclosure. Exploitable via mc_gross.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-9189 has been found in Contact Form 7 – PayPal & Stripe Add-on (WordPress plugin).
Attackers can target a specific entry point like mc_gross over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Contact Form 7 – PayPal & Stripe Add-on (WordPress plugin) CVE-2026-9189" on the vendor's site.
CVE-2026-9189 (Contact Form 7 – PayPal & Stripe Add-on (WordPress plugin)) — CWE-345 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: mc_gross / mc_currency / receiver_email / invoice
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-345) exists in Contact Form 7 – PayPal & Stripe Add-on (WordPress plugin). Attackers reach the vulnerable code path via mc_gross without authentication.
Check the vendor advisory for the affected versions of Contact Form 7 – PayPal & Stripe Add-on (WordPress plugin). Attack surface: mc_gross / mc_currency / receiver_email / invoice.
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Contact Form 7 – PayPal & Stripe Add-on (WordPress plugin) を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。