CVE-2025-49333 in Simple Membership Plugin
Summary
by MITRE • 06/06/2025
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in wp.insider Simple Membership allows Stored XSS. This issue affects Simple Membership: from n/a through 4.6.3.
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Analysis
by VulDB Data Team • 06/06/2025
This vulnerability represents a critical cross-site scripting flaw within the wp.insider Simple Membership plugin, specifically targeting versions ranging from an unspecified initial version through 4.6.3. The issue stems from inadequate input sanitization during web page generation processes, creating a persistent security weakness that enables attackers to inject malicious scripts into web pages viewed by other users. The vulnerability classifies under CWE-79 which defines improper neutralization of input during web page generation as a fundamental weakness in web application security. This particular implementation flaw allows for stored cross-site scripting attacks, meaning that malicious payloads can be permanently stored on the server and subsequently executed whenever affected pages are accessed by unsuspecting users.
The technical exploitation of this vulnerability occurs when user input is not properly validated or sanitized before being rendered in web pages generated by the Simple Membership plugin. Attackers can leverage this weakness by submitting malicious script code through input fields that are subsequently stored within the application's database or storage mechanisms. When other users access pages containing this stored content, their browsers execute the injected scripts, potentially leading to session hijacking, credential theft, or redirection to malicious websites. The stored nature of this XSS vulnerability distinguishes it from reflected XSS attacks, as the malicious code persists and affects multiple users over time rather than requiring specific user interaction with a crafted link.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform unauthorized actions on behalf of affected users. This includes accessing sensitive user data, modifying membership configurations, or even gaining administrative privileges if the targeted users have elevated permissions. The vulnerability's persistence means that once exploited, the malicious scripts continue to execute for all users until the stored input is removed or the vulnerability is patched. This makes the attack surface particularly dangerous for membership-based websites where user trust and data protection are paramount. The vulnerability affects all versions up to and including 4.6.3, indicating that organizations running these plugin versions are exposed to potential exploitation without immediate remediation.
Mitigation strategies for this vulnerability should prioritize immediate patching of the Simple Membership plugin to the latest available version that addresses the XSS flaw. Security administrators should also implement additional defensive measures such as input validation and output encoding at multiple layers of the application architecture. The implementation of Content Security Policy (CSP) headers can provide an additional barrier against script execution, while regular security audits and penetration testing should be conducted to identify similar weaknesses. Organizations should also consider implementing web application firewalls and monitoring for suspicious input patterns that may indicate attempted exploitation of this vulnerability. This approach aligns with the ATT&CK framework's mitigation recommendations for web application attacks, emphasizing the importance of both preventive measures and detection capabilities to protect against persistent XSS vulnerabilities.