CVE-2025-3247 in Contact Form 7 Plugin
Summary
by MITRE • 04/16/2025
The Contact Form 7 plugin for WordPress is vulnerable to Order Replay in all versions up to, and including, 6.0.5 via the 'wpcf7_stripe_skip_spam_check' function due to insufficient validation on a user controlled key. This makes it possible for unauthenticated attackers to reuse a single Stripe PaymentIntent for multiple transactions. Only the first transaction is processed via Stripe, but the plugin sends a successful email message for each transaction, which may trick an administrator into fulfilling each order.
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Analysis
by VulDB Data Team • 04/16/2025
The vulnerability identified as CVE-2025-3247 affects the Contact Form 7 plugin for WordPress, specifically impacting versions up to and including 6.0.5. This represents a critical security flaw that exploits the plugin's handling of Stripe payment processing through the 'wpcf7_stripe_skip_spam_check' function. The issue stems from inadequate input validation on user-controlled parameters, creating a pathway for malicious actors to manipulate payment workflows. The vulnerability enables unauthorized users to exploit the payment processing system without proper authentication, fundamentally compromising the integrity of transaction handling within the plugin's payment gateway integration.
The technical flaw manifests through insufficient validation of a user-controlled key parameter within the Stripe PaymentIntent processing workflow. When the 'wpcf7_stripe_skip_spam_check' function processes payment requests, it fails to properly verify the authenticity and uniqueness of the PaymentIntent identifier. This allows attackers to submit the same PaymentIntent token multiple times, effectively enabling order replay attacks. The system accepts these repeated submissions without proper validation, treating each request as a legitimate transaction. The vulnerability operates at the intersection of improper input validation and inadequate session management, creating a scenario where the backend system processes the same payment token repeatedly.
The operational impact of this vulnerability extends beyond simple financial fraud, creating a complex attack surface that can deceive both system administrators and customers. While only the initial transaction actually processes through Stripe's payment infrastructure, the plugin's logic sends confirmation emails for each attempted transaction, creating a false sense of successful processing. This deceptive behavior can lead administrators to believe that multiple orders have been properly fulfilled, potentially resulting in inventory discrepancies, customer service issues, and fraudulent chargeback scenarios. The vulnerability essentially creates a false positive confirmation mechanism that can be exploited for repeated fraudulent activities.
Security practitioners should recognize this vulnerability as a variant of CWE-20, Improper Input Validation, combined with elements of CWE-345 Insufficient Verification of Data Authenticity. The attack pattern aligns with ATT&CK technique T1071.004 Application Layer Protocol: DNS, as it exploits protocol handling within web application interfaces. Organizations using Contact Form 7 with Stripe integration must immediately implement mitigation strategies including updating to patched versions, implementing additional validation layers, and monitoring for unusual transaction patterns. The vulnerability also demonstrates characteristics of credential stuffing and session replay attacks, making it particularly dangerous for e-commerce environments where payment processing integrity is paramount.
The remediation approach requires immediate patching of the Contact Form 7 plugin to version 6.0.6 or later, which contains the necessary validation fixes for the 'wpcf7_stripe_skip_spam_check' function. Administrators should also implement additional security controls including rate limiting on payment processing endpoints, enhanced logging of transaction attempts, and verification of PaymentIntent status before processing repeat requests. Network monitoring should be enhanced to detect unusual patterns of email notifications coinciding with payment processing activities. Organizations should conduct comprehensive security assessments of their payment processing workflows and consider implementing multi-factor authentication for administrative access to payment-related plugin configurations. The vulnerability underscores the importance of proper input validation in payment processing systems and highlights the need for robust transaction integrity checks in web applications.