CVE-2023-2733 in MStore API Plugin
Summary
by MITRE • 05/25/2023
The MStore API plugin for WordPress is vulnerable to authentication bypass in versions up to, and including, 3.9.0. This is due to insufficient verification on the user being supplied during the coupon redemption REST API request through the plugin. This makes it possible for unauthenticated attackers to log in as any existing user on the site, such as an administrator, if they have access to the user id.
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Analysis
by VulDB Data Team • 04/09/2026
The vulnerability identified in CVE-2023-2733 affects the MStore API plugin for WordPress, specifically targeting versions up to and including 3.9.0. This authentication bypass flaw represents a critical security weakness that fundamentally undermines the integrity of user authentication mechanisms within WordPress installations. The vulnerability exists within the coupon redemption REST API endpoint, which is designed to handle promotional code redemptions but fails to properly validate user credentials during the authentication process. This creates a pathway for malicious actors to exploit the system's trust model and gain unauthorized access to user accounts with elevated privileges.
The technical implementation of this vulnerability stems from inadequate input validation and authentication checks within the plugin's REST API framework. When an attacker submits a coupon redemption request through the API, the system does not sufficiently verify the authenticity of the user attempting to redeem the coupon. This weakness allows for arbitrary user impersonation where an attacker with knowledge of a valid user ID can potentially authenticate as that user without proper credentials. The flaw essentially removes the authentication barrier that should normally prevent unauthorized access, enabling attackers to leverage existing user accounts for malicious activities. This issue directly relates to CWE-287, which addresses improper authentication vulnerabilities, and demonstrates how insufficient validation can lead to complete system compromise.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it provides attackers with the capability to assume administrator privileges and execute arbitrary actions within the WordPress environment. An attacker who discovers a valid user ID can potentially escalate their privileges and gain full control over the website's content management system, user accounts, and potentially even server-level access. This authentication bypass enables a wide range of malicious activities including content manipulation, user account hijacking, data exfiltration, and the installation of malicious plugins or themes. The vulnerability's severity is amplified by the fact that it requires minimal information from attackers - simply knowing a valid user ID is sufficient to exploit the flaw, making it particularly dangerous in environments where user ID enumeration might be possible through other means.
Mitigation strategies for this vulnerability should prioritize immediate plugin updates to versions that address the authentication bypass flaw, as developers have likely released patches to resolve the issue. Organizations should implement comprehensive monitoring of REST API access patterns to detect anomalous authentication attempts and user impersonation activities. Network-level controls such as API rate limiting and IP-based access restrictions can help reduce the attack surface while patches are deployed. Security teams should conduct thorough user account reviews to identify any unauthorized access attempts and implement stronger authentication measures including multi-factor authentication for administrative accounts. Additionally, regular security audits of WordPress plugins and themes should be performed to identify similar vulnerabilities in other third-party components. The remediation process should also include reviewing and hardening the REST API endpoints to ensure proper authentication checks are implemented, aligning with ATT&CK technique T1078 which addresses valid accounts and privilege escalation through legitimate credentials. Organizations must also consider implementing web application firewalls and security monitoring solutions that can detect and block malicious API requests attempting to exploit authentication bypass vulnerabilities.