CVE-2025-50051 in WP-Members Plugin
Summary
by MITRE • 06/20/2025
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Chad Butler WP-Members allows Stored XSS. This issue affects WP-Members: from n/a through 3.5.4.
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Analysis
by VulDB Data Team • 06/23/2025
This vulnerability represents a critical cross-site scripting flaw that undermines the security posture of the WP-Members plugin for wordpress systems. The issue stems from inadequate input sanitization during web page generation processes, creating an environment where malicious scripts can be persistently stored and subsequently executed in the browsers of unsuspecting users. The vulnerability affects all versions of WP-Members from the initial release through version 3.5.4, indicating a prolonged exposure window that could have allowed extensive exploitation. The stored nature of this XSS vulnerability means that malicious payloads are not limited to a single request but remain embedded within the application's data storage, making them particularly dangerous as they can affect multiple users over extended periods. This flaw directly maps to CWE-79 which defines improper neutralization of input during web page generation as a fundamental weakness in web application security.
The technical exploitation of this vulnerability occurs when authenticated users with sufficient privileges submit malicious input through plugin interfaces that are then stored in the database or application memory. When other users access pages that render this stored content, the malicious javascript code executes within their browser context, potentially stealing session cookies, redirecting users to malicious sites, or performing unauthorized actions on behalf of the victims. The vulnerability's impact is amplified by the fact that it operates within a membership management plugin, which typically handles sensitive user data and authentication mechanisms. This creates a potential attack vector for privilege escalation and data exfiltration, as the stored XSS can be leveraged to compromise user sessions and access restricted areas of the wordpress installation. The attack surface is further expanded by the fact that many wordpress installations rely heavily on plugin functionality for core business operations, making the exploitation of such vulnerabilities particularly damaging.
The operational consequences of this vulnerability extend beyond simple script execution to encompass broader security implications for wordpress environments. Organizations using affected WP-Members versions face potential data breaches, user account compromises, and reputational damage from successful XSS attacks. The vulnerability's persistence means that even after initial exploitation, malicious code can continue to affect users until the underlying input sanitization issues are resolved through patching or other mitigations. Security teams must consider this vulnerability as a potential entry point for more sophisticated attacks, including credential theft, session hijacking, and lateral movement within compromised networks. The attack pattern aligns with ATT&CK technique T1531 which describes the use of malicious code execution to gain access to systems, and T1071.001 which covers application layer protocol usage for command and control communications.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected WP-Members installations to version 3.5.5 or later, which contains the necessary input sanitization fixes. Organizations should implement comprehensive input validation and output encoding mechanisms across all user-submitted content within their wordpress installations. Network-based mitigations such as web application firewalls can provide additional protection layers, though these should not replace proper code-level fixes. Security monitoring should include detection of suspicious user activity patterns that might indicate exploitation attempts, particularly around membership management interfaces. Regular security audits of wordpress plugins and themes should be conducted to identify similar vulnerabilities, with particular attention to input handling and sanitization practices. The incident response plan should include procedures for rapid patch deployment and user session invalidation in case of confirmed exploitation, as well as communication protocols for informing affected users about potential security breaches.