CVE-2026-103427
Received Received - Intake

Stored XSS in Simple Membership WordPress Plugin

Publication date: 2026-10-10

Last updated on: 2026-10-10

Assigner: Wordfence

Description
The Simple Membership plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'country' parameter in all versions up to, and including, 4.8.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Unauthenticated attackers may also exploit this vulnerability when the plugin's Enable Free Membership feature is turned on, as it permits anonymous front-end registration and profile submission.

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Meta Information

Published
2026-10-10
Last Modified
2026-10-10
Generated
2026-10-10
AI Q&A
2026-10-10
EPSS Evaluated
N/A
NVD
CVE-2026-103427
EUVD
EUVD-2026-96206

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
wpinsider-1 Simple Membership 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

This vulnerability is a Stored Cross-Site Scripting (XSS) flaw in the Simple Membership WordPress plugin up to version 4.8.4. It occurs due to insufficient input sanitization and output escaping in the 'country' parameter. Attackers with subscriber-level access or higher can inject malicious scripts into pages. If the plugin's free membership feature is enabled, unauthenticated attackers can also exploit this during registration or profile submission.

Detection Guidance

To detect this vulnerability, inspect WordPress sites using the Simple Membership plugin up to version 4.8.4. Check for suspicious scripts in pages where the 'country' parameter is used. Review user profiles and membership pages for unexpected JavaScript injections. Use security plugins like Wordfence to scan for XSS vulnerabilities.

Impact Analysis

This vulnerability allows attackers to inject malicious scripts into web pages. When users access these pages, the scripts execute, potentially stealing cookies, session tokens, or other sensitive data. It could also lead to account takeover, defacement of websites, or spreading malware to visitors.

Compliance Impact

This vulnerability could lead to unauthorized data access or modification, violating GDPR's data protection requirements and HIPAA's safeguards for protected health information. Organizations using the affected plugin may face compliance violations, legal penalties, and reputational damage if exploited.

Mitigation Strategies

Update the Simple Membership plugin to version 4.8.5 or later immediately. Disable the 'Enable Free Membership' feature if not required. Implement input sanitization for user-submitted data. Monitor for unauthorized script injections in pages and user profiles.

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