CVE-2026-27401 in PayPal Express Checkout Plugin
Summary
by MITRE • 10/29/2026
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 1.62.0.
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Analysis
by VulDB Data Team • 10/29/2026
The vulnerability identified in the YITH PayPal Express Checkout plugin for WordPress, specifically affecting versions up to and including 1.62.0, 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 validate user roles or session states before executing sensitive operations. An attacker could potentially exploit these misconfigurations to perform actions such as modifying order details, bypassing payment gateways, or accessing administrative features without proper authentication. The absence of robust server-side checks means that client-side validations can be easily circumvented using standard web exploitation tools, allowing malicious users to send crafted requests that the application processes as legitimate due to insufficient authorization logic.
The operational impact of this vulnerability extends beyond simple unauthorized access; it compromises the trustworthiness of the entire checkout pipeline. Attackers could exploit this flaw to conduct fraud by altering order totals, redirecting payments to fraudulent accounts, or extracting sensitive customer information such as billing addresses and payment tokens stored in session variables during the express checkout process. This not only leads to direct financial losses for merchants but also exposes them to regulatory penalties under data protection laws like GDPR if personal identifiable information is compromised. Furthermore, the reputation of the e-commerce platform suffers significantly when customers experience interrupted transactions or discover that their payment details were mishandled due to security lapses in third-party plugins.
Industry frameworks such as MITRE ATT&CK classify this type of vulnerability under techniques related to Privilege Escalation and Defense Evasion, specifically where attackers leverage misconfigured permissions to gain higher-level access within the application environment. The lack of proper authorization checks aligns with common patterns observed in web application attacks where developers rely on implicit trust assumptions rather than explicit verification mechanisms. This oversight creates an attack surface that is easily exploitable by automated scanning tools and manual penetration testers alike, making it a high-priority target for malicious actors seeking to compromise e-commerce infrastructure.
To mitigate this risk, immediate action must be taken by updating the YITH PayPal Express Checkout plugin to version 1.62.1 or later, where these authorization checks have been corrected. Administrators should also implement strict input validation and ensure that all sensitive operations require explicit verification of user roles against a centralized access control list. Additionally, deploying Web Application Firewalls with rules tailored to detect abnormal checkout behavior can provide an additional layer of defense by identifying and blocking requests that exhibit patterns consistent with authorization bypass attempts. Regular security audits and code reviews focusing on authentication and authorization logic are essential to prevent similar vulnerabilities from being introduced in future updates or other plugins integrated into the WooCommerce ecosystem.