CVE-2026-13399 in Payment Plugins for PayPal WooCommerce Plugin
Summary
by MITRE • 08/07/2026
The Payment Plugins for PayPal WooCommerce WordPress plugin before 2.0.20 does not have proper authorization checks on a REST endpoint, allowing unauthenticated users to bypass payments
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Analysis
by VulDB Data Team • 08/07/2026
The vulnerability resides in the Payment Plugins for PayPal WooCommerce WordPress plugin version 2.0.19 and earlier, where a critical authorization flaw exists within a REST endpoint implementation. This weakness enables unauthenticated attackers to exploit the payment processing functionality without proper authentication or authorization, effectively bypassing the entire payment validation mechanism that should normally require user authentication and payment verification. The vulnerability directly impacts the core payment workflow of WooCommerce stores using PayPal integration, creating a significant security risk for merchants who rely on this plugin for transaction processing.
The technical flaw manifests as a missing authorization check within the REST API endpoint responsible for handling payment operations. According to CWE-863, this represents an "Authorization Bypass Through User-Controlled Key" vulnerability where the system fails to properly validate user permissions before executing privileged operations. The REST endpoint in question likely accepts payment parameters and transaction details without verifying that the requesting user possesses legitimate authorization to perform such actions. This absence of proper access control allows any malicious actor with knowledge of the endpoint URL to submit payment requests directly, circumventing the normal authentication flow that should occur during checkout processes.
The operational impact of this vulnerability extends beyond simple unauthorized payment processing, as it fundamentally undermines the integrity of the payment ecosystem within WordPress e-commerce environments. Attackers could potentially process fraudulent transactions, manipulate payment amounts, or create unauthorized payment records that would appear legitimate within the merchant's system. This vulnerability aligns with ATT&CK technique T1078.004, which covers "Valid Accounts: Cloud Accounts" where adversaries use valid credentials to gain access to systems, though in this case the flaw allows bypassing authentication entirely rather than exploiting existing accounts. The implications include potential financial loss for merchants, compromised customer payment data, and possible regulatory violations depending on local payment processing requirements.
Mitigation strategies must address both immediate remediation and long-term security improvements within the plugin architecture. Organizations should immediately update to version 2.0.20 or later where proper authorization checks have been implemented to prevent unauthenticated access to payment endpoints. Additionally, administrators should conduct thorough audits of all REST API endpoints within their WordPress installations to identify similar authorization gaps that may exist in other plugins or custom implementations. Security monitoring should include detection of unauthorized access attempts to payment-related endpoints and implementation of rate limiting to prevent automated exploitation attempts. The fix typically involves implementing proper authentication checks using WordPress's built-in user verification mechanisms before allowing any payment processing operations to proceed, ensuring compliance with security standards such as those outlined in the OWASP Top Ten and NIST cybersecurity frameworks for web application security.