CVE-2024-9222 in Paid Membership Subscriptions Plugin
Summary
by MITRE • 10/02/2024
The Paid Membership Subscriptions – Effortless Memberships, Recurring Payments & Content Restriction plugin for WordPress is vulnerable to Reflected Cross-Site Scripting due to the use of add_query_arg without appropriate escaping on the URL in all versions up to, and including, 2.12.8. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.
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Analysis
by VulDB Data Team • 03/08/2025
The vulnerability identified as CVE-2024-9222 affects the Paid Membership Subscriptions plugin for WordPress, specifically targeting versions up to and including 2.12.8. This plugin serves as a comprehensive membership management solution that handles user subscriptions, recurring payments, and content restriction across WordPress websites. The security flaw manifests in how the plugin processes URL parameters within its administrative interfaces and frontend components, creating an avenue for malicious actors to exploit reflected cross-site scripting vulnerabilities. The issue arises from the plugin's improper handling of query arguments that are added to URLs without adequate HTML escaping mechanisms, making it susceptible to injection attacks that can execute malicious scripts in the context of a user's browser session.
The technical exploitation of this vulnerability occurs through the add_query_arg function which is commonly used in WordPress development to construct URLs with additional parameters. When this function is employed without proper sanitization or escaping of the input values, it creates a scenario where attacker-controlled data can be injected directly into URL parameters. This reflected XSS vulnerability allows unauthenticated attackers to craft malicious URLs that, when clicked by an unsuspecting user, will execute arbitrary JavaScript code within the user's browser context. The attack vector is particularly dangerous because it requires no authentication and can be delivered through social engineering techniques such as phishing emails or compromised website links, making it a significant risk to both administrators and end users of affected WordPress installations.
The operational impact of CVE-2024-9222 extends beyond simple script injection, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, and redirection to malicious websites. When a user clicks on a crafted link containing the malicious payload, the injected scripts can access the user's session cookies, potentially allowing attackers to impersonate legitimate users and gain unauthorized access to membership areas, administrative panels, or other restricted content. The vulnerability affects the plugin's ability to maintain secure user sessions and can compromise the integrity of membership data, subscription management, and content restriction mechanisms that the plugin is designed to protect. This poses a serious threat to website owners who rely on the plugin for managing paid memberships and protecting premium content from unauthorized access.
Security mitigations for this vulnerability should prioritize immediate patching of the affected plugin to the latest available version that contains the necessary escaping mechanisms for URL parameters. System administrators should implement comprehensive monitoring of user activity and URL access patterns to detect potential exploitation attempts. The implementation of Content Security Policy headers can provide additional defense-in-depth measures by restricting the sources from which scripts can be executed within the browser context. Network-level protections such as web application firewalls should be configured to detect and block malicious URL patterns associated with known XSS attack vectors. Organizations should also conduct thorough security assessments of their WordPress installations to identify other potentially vulnerable plugins or themes that may be susceptible to similar reflected XSS vulnerabilities. This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and represents a typical example of how improper input validation and output encoding can create security risks in web applications. The attack pattern follows standard ATT&CK techniques for initial access through malicious links, and could potentially enable privilege escalation if attackers can leverage the compromised sessions to access administrative functions within the membership system.