CVE-2026-81767 in Simple Payment Plugin
Summary
by MITRE • 08/28/2026
Unauthenticated Broken Access Control in Simple Payment <= 2.5.2 versions.
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Analysis
by VulDB Data Team • 08/28/2026
The vulnerability identified as an unbroken access control issue within the Simple Payment plugin, specifically affecting versions up to and including 2.5.2, represents a critical failure in server-side authorization mechanisms. This flaw allows attackers who are not authenticated or lack sufficient privileges to perform actions that should be restricted to authorized users, such as administrators or verified customers. The core of this vulnerability lies in the application's inability to properly verify whether the user initiating an action has the requisite permissions for that specific operation. In many WordPress-based e-commerce solutions, plugins often handle sensitive financial data and transaction states, making robust access control paramount. When these controls are bypassed due to missing checks or flawed logic, it opens a direct path for malicious actors to manipulate payment records, alter order statuses, or potentially extract confidential customer information without any form of legitimate authentication credentials.
From a technical perspective, this type of vulnerability is commonly categorized under CWE-284, which describes Improper Access Control. The exploitation typically involves crafting specific HTTP requests that target endpoints responsible for processing payments, updating transaction details, or managing order metadata. Because the plugin fails to validate the session state or user role associated with these requests before executing them, an attacker can simply send a POST request containing modified parameters to change the outcome of a payment process. For instance, an attacker might be able to mark an unpaid invoice as paid, thereby bypassing financial obligations, or modify transaction amounts to favor their own interests. This lack of enforcement means that the security boundary defined by user roles is effectively non-existent for these specific functions, allowing any internet-facing client with knowledge of the API endpoints to interact with them freely.
The operational impact of this vulnerability extends beyond simple data manipulation and poses significant risks to both merchants and customers. For business owners relying on Simple Payment for revenue generation, successful exploitation could lead to direct financial loss through fraudulent transactions or chargebacks resulting from altered order statuses. Furthermore, if the plugin stores sensitive payment details such as credit card numbers or billing addresses in a manner that becomes accessible due to this access control failure, it constitutes a severe data breach violation of standards like PCI DSS and GDPR. Customers may suffer from identity theft or unauthorized charges on their accounts. The integrity of the entire e-commerce platform is compromised, leading to potential reputational damage and loss of consumer trust, which can have long-term negative effects on business viability.
This vulnerability aligns with several techniques found in the MITRE ATT&CK framework, particularly those related to privilege escalation or unauthorized access to resources. It reflects patterns seen in attacks where adversaries exploit misconfigured permissions to gain initial footholds or move laterally within a system by manipulating administrative functions without proper authorization. The absence of strict input validation combined with weak session management creates an environment ripe for automated exploitation tools that scan for common WordPress plugin vulnerabilities. Attackers often use these flaws not just for immediate financial gain but as entry points into the broader server infrastructure, potentially leading to further compromise such as remote code execution if other related vulnerabilities exist within the same application stack.
To mitigate this risk, it is imperative for administrators of websites using Simple Payment versions 2.5.2 and below to update the plugin immediately to a patched version where these access control checks have been implemented correctly. Developers must ensure that all API endpoints enforce strict verification of user roles before processing any state-changing requests. Implementing additional layers of security, such as CSRF tokens for form submissions and rate limiting on sensitive endpoints, can further reduce the attack surface. Regular security audits and penetration testing should be conducted to identify similar logic flaws in other plugins or custom code within the WordPress environment. By adhering to these remediation steps, organizations can restore the integrity of their payment processing systems and protect both their financial interests and customer data from unauthorized manipulation.