CVE-2015-9528 in Software Licensing Extension
Summary
by MITRE
The Easy Digital Downloads (EDD) Software Licensing 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 • 02/07/2025
The vulnerability CVE-2015-9528 represents a cross-site scripting weakness in the Easy Digital Downloads software licensing extension for WordPress platforms. This security flaw affects multiple versions of the EDD extension across several major release branches including 1.8.x through 2.3.x, specifically before the mentioned patch versions. The vulnerability stems from improper handling of query arguments within the add_query_arg function, which creates opportunities for malicious actors to inject harmful scripts into web applications.
The technical implementation of this vulnerability involves the misuse of WordPress's add_query_arg function which is designed to handle URL parameter manipulation safely. However, in the affected versions of the EDD licensing extension, this function is not properly sanitizing or escaping user-supplied input before incorporating it into dynamically generated URLs. When users visit pages that utilize these vulnerable functions, malicious scripts can be embedded in query parameters and executed in the context of other users' browsers, potentially leading to session hijacking, data theft, or unauthorized administrative actions.
The operational impact of this vulnerability extends beyond simple script injection as it can be exploited by attackers to gain unauthorized access to WordPress sites running vulnerable versions of the EDD extension. Attackers can craft malicious URLs containing script payloads that, when clicked by unsuspecting users or administrators, execute in their browsers. This creates a persistent threat vector that can be leveraged for various malicious activities including credential theft, privilege escalation, or even complete site compromise. The vulnerability affects the core functionality of the software licensing extension, which typically handles product licensing, activation keys, and other sensitive administrative features.
Mitigation strategies for CVE-2015-9528 primarily involve updating to the patched versions of the Easy Digital Downloads extension as specified in the advisory. Organizations should immediately apply the security patches released by the EDD development team for all affected versions. Additionally, implementing proper input validation and output escaping mechanisms can provide defense-in-depth measures. The vulnerability aligns with CWE-79 which categorizes cross-site scripting flaws, and can be mapped to ATT&CK technique T1190 for exploiting vulnerabilities in web applications. Security monitoring should include detection of suspicious query parameter patterns and regular vulnerability scanning of WordPress installations to identify unpatched components. System administrators should also consider implementing web application firewalls and content security policies to reduce the potential impact of such vulnerabilities.