CVE-2015-9514 in Free Downloads Extension
Summary
by MITRE
The Easy Digital Downloads (EDD) Free Downloads extension for WordPress, as used with EDD 1.8.x before 1.8.7, 1.9.x before 1.9.10, 2.0.x before 2.0.5, 2.1.x before 2.1.11, 2.2.x before 2.2.9, and 2.3.x before 2.3.7, has XSS because add_query_arg is misused.
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Analysis
by VulDB Data Team • 02/08/2025
The CVE-2015-9514 vulnerability represents a cross-site scripting flaw within the Easy Digital Downloads WordPress plugin ecosystem, specifically affecting the Free Downloads extension. This vulnerability manifests in versions of the Easy Digital Downloads plugin prior to the specified patched releases across multiple version branches including 1.8.x, 1.9.x, 2.0.x, 2.1.x, 2.2.x, and 2.3.x. The flaw stems from improper usage of the add_query_arg WordPress function, which is designed to safely manipulate query parameters in URLs. When developers misuse this function by directly incorporating user-supplied input into query arguments without proper sanitization or escaping, it creates opportunities for malicious actors to inject malicious scripts into web pages viewed by other users.
The technical exploitation of this vulnerability occurs when an attacker can manipulate query parameters that are subsequently rendered in web pages without adequate output escaping. The add_query_arg function, when misused, fails to properly sanitize the input values before they are appended to URLs, allowing malicious payloads to persist in the query string. This creates a persistent XSS vector where user input flows directly into the HTML output context without proper security controls. The vulnerability is particularly concerning because it affects a widely-used e-commerce plugin that handles financial transactions, making it attractive to attackers seeking to compromise user sessions or steal sensitive data. The flaw aligns with CWE-79, which describes cross-site scripting vulnerabilities, and demonstrates how improper input handling can create security weaknesses in web applications.
The operational impact of CVE-2015-9514 extends beyond simple script injection, potentially enabling attackers to perform session hijacking, deface websites, or redirect users to malicious domains. Attackers could craft specially formatted URLs containing malicious JavaScript code that would execute in the context of authenticated users' browsers, particularly those with administrative privileges. This vulnerability could be exploited through various attack vectors including social engineering campaigns where users are tricked into clicking malicious links, or through automated scanning tools that identify vulnerable plugin installations. The widespread adoption of Easy Digital Downloads makes this vulnerability particularly dangerous as it could affect numerous online stores and businesses conducting digital commerce. The attack surface is further expanded by the fact that the vulnerability exists in multiple versions, increasing the number of potentially compromised systems.
Mitigation strategies for CVE-2015-9514 require immediate patching of affected plugin versions to the latest releases containing the security fixes. System administrators should ensure all instances of the Easy Digital Downloads plugin are updated to versions 1.8.7, 1.9.10, 2.0.5, 2.1.11, 2.2.9, and 2.3.7 or later. Additionally, implementing proper input validation and output escaping mechanisms should be enforced in custom plugin development practices, particularly when handling user-supplied data in URL parameters. Organizations should conduct thorough vulnerability assessments to identify all potentially affected installations and implement web application firewalls to detect and block malicious query parameter injection attempts. Regular security monitoring and automated patch management processes are essential to prevent similar vulnerabilities from being exploited in the future. This vulnerability also underscores the importance of following secure coding practices as outlined in the OWASP Top Ten and the ATT&CK framework's application of defensive techniques for input validation and output encoding to prevent XSS attacks.