CVE-2026-111409 in PayPal Express Checkout Plugin
Summary
by MITRE • 10/16/2026
Missing Authorization vulnerability in YITH YITH PayPal Express Checkout for WooCommerce yith-paypal-express-checkout-for-woocommerce allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects YITH PayPal Express Checkout for WooCommerce: from n/a through 1.61.0.
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Analysis
by VulDB Data Team • 10/16/2026
The vulnerability identified in the YITH PayPal Express Checkout plugin for WordPress, specifically affecting versions up to and including 1.61.0, represents a critical failure in access control mechanisms that allows unauthorized actors to manipulate checkout processes or bypass payment verification steps. This flaw is categorized under CWE-862, which denotes Missing Authorization, indicating that the application fails to properly verify whether an authenticated user has the necessary permissions to perform specific actions within the e-commerce workflow. In the context of WooCommerce, a widely used content management system for online retail, such vulnerabilities can have severe financial and operational consequences because they directly impact the integrity of transaction processing and customer data handling.
From a technical perspective, this incorrect configuration of access control security levels suggests that certain endpoints or functions within the plugin do not adequately check user roles or session states before executing sensitive operations. An attacker could potentially exploit these unprotected routes to modify order details, bypass payment gateways such as PayPal Express Checkout, or manipulate cart contents without proper authentication checks. The absence of robust server-side validation allows malicious users to send crafted requests that simulate legitimate checkout processes, effectively circumventing the intended security boundaries established by the plugin developers and WordPress core permissions systems.
The operational impact of this vulnerability is significant for any business relying on WooCommerce for sales operations. Successful exploitation could lead to unauthorized transactions where goods are shipped without payment being processed correctly, resulting in direct financial loss through fraud or chargebacks. Additionally, attackers might exploit these weaknesses to gain deeper access into the WordPress environment by leveraging elevated privileges obtained during the checkout process. This can serve as a foothold for further attacks such as data exfiltration of customer personally identifiable information (PII), credit card details stored in transient states, or installation of persistent backdoors within the website infrastructure.
This vulnerability aligns with MITRE ATT&CK technique T1078, Valid Accounts, particularly when combined with other techniques like T1505.003, Server Software Component: Web Shell, if the attacker uses the access to upload malicious files or modify existing ones due to insufficient permission checks on file management features often exposed in e-commerce plugins. Furthermore, it relates to CWE-284 Improper Access Control, highlighting a systemic issue where security controls are either not implemented correctly or can be bypassed through parameter manipulation and request forgery attacks targeting the checkout flow logic.
Mitigation strategies must prioritize immediate remediation by updating the YITH PayPal Express Checkout plugin to version 1.61.1 or later, where these access control flaws have been addressed by implementing stricter role-based checks on all critical endpoints. Administrators should also enforce strict input validation and output encoding practices across their WooCommerce installations to prevent related injection attacks that often accompany authorization bypasses. Regular security audits focusing on authentication and authorization logic are recommended, along with the implementation of Web Application Firewalls (WAFs) configured to detect anomalous checkout patterns indicative of exploitation attempts. Keeping all WordPress core files, themes, and plugins up to date remains the most effective defense against such misconfigurations that undermine the trust model essential for secure e-commerce operations.