CVE-2014-5240 in WordPress
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in wp-includes/pluggable.php in WordPress before 3.9.2, when Multisite is enabled, allows remote authenticated administrators to inject arbitrary web script or HTML, and obtain Super Admin privileges, via a crafted avatar URL.
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Analysis
by VulDB Data Team • 03/28/2022
The vulnerability identified as CVE-2014-5240 represents a critical cross-site scripting flaw within WordPress core functionality that specifically targets installations utilizing the multisite feature. This vulnerability exists in the wp-includes/pluggable.php file and affects WordPress versions prior to 3.9.2, creating a significant security risk for administrators who manage multiple sites within a single WordPress installation. The flaw exploits the way WordPress handles avatar URLs in multisite environments, allowing authenticated administrators with sufficient privileges to manipulate the system through malicious input.
The technical exploitation of this vulnerability occurs through the manipulation of avatar URL parameters within the WordPress multisite administration interface. When an authenticated administrator with appropriate permissions submits a crafted avatar URL containing malicious script code, the vulnerability allows this code to be executed within the context of other users' browsers who view the affected profile or user listing pages. This cross-site scripting condition enables attackers to inject arbitrary web script or HTML content that persists in the system and can be executed by other users. The vulnerability is particularly dangerous because it operates within the administrative context, allowing the attacker to escalate privileges from regular administrator to Super Admin level.
The operational impact of CVE-2014-5240 extends beyond simple script injection, as it provides attackers with the capability to completely compromise the WordPress multisite installation. By obtaining Super Admin privileges, an attacker can manipulate all aspects of the multisite network, including creating new users, modifying existing user permissions, installing malicious plugins, modifying themes, and accessing sensitive data across all sites within the network. This privilege escalation capability fundamentally undermines the security model of WordPress multisite installations, where administrators are expected to have limited scope within their respective sites. The vulnerability affects the core WordPress authentication and authorization mechanisms, potentially leading to complete network compromise and data exfiltration.
This vulnerability maps to CWE-79 Cross-site Scripting and aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as well as T1548.003 for abuse of privileges. The attack surface is particularly concerning in enterprise environments where WordPress multisite installations are commonly deployed for managing multiple organizational websites. Security professionals should consider this vulnerability as part of the broader threat landscape for content management systems, particularly when evaluating the security posture of multi-tenant WordPress installations. Organizations should immediately implement the patch for WordPress 3.9.2 or higher, as the vulnerability does not require any special conditions beyond having a valid administrative account. Additionally, implementing proper input validation and output encoding measures in custom plugins or themes that interact with avatar functionality can provide additional defense-in-depth protection against similar vulnerabilities.
The remediation strategy for CVE-2014-5240 requires immediate patching of affected WordPress installations to version 3.9.2 or later, where the vulnerability has been addressed through proper input sanitization of avatar URLs. Network administrators should also implement monitoring for suspicious avatar URL submissions and user account activity that might indicate exploitation attempts. Regular security audits of WordPress installations should include verification of multisite configuration settings and user privilege assignments to prevent unauthorized escalation. The vulnerability demonstrates the importance of maintaining current WordPress core versions and implementing robust security practices within multisite environments, where the attack surface expands significantly due to shared administrative interfaces and network-level access controls.