CVE-2019-16219 in WordPress
Summary
by MITRE
WordPress before 5.2.3 allows XSS in shortcode previews.
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Analysis
by VulDB Data Team • 12/19/2023
WordPress versions prior to 5.2.3 contained a cross-site scripting vulnerability in the shortcode preview functionality that could be exploited by authenticated attackers with contributor-level permissions or higher. This vulnerability falls under CWE-79 Improper Neutralization of Input During Web Page Generation, specifically affecting the rendering of user-supplied content within the administrative interface. The flaw existed in the way WordPress processed and displayed shortcode previews, where user input was not properly sanitized before being rendered in the browser context. Attackers could craft malicious shortcodes containing script tags or other malicious payloads that would execute in the context of a victim administrator's browser when they viewed the shortcode preview. This vulnerability was particularly dangerous because it required minimal privileges to exploit, as contributors and above could access the preview functionality without additional restrictions. The attack vector involved navigating to the post editing interface, creating or modifying a shortcode with malicious content, and then viewing the preview which would execute the injected script. This could lead to session hijacking, privilege escalation, or data exfiltration from the compromised administrator account. The vulnerability was addressed in WordPress version 5.2.3 through proper input sanitization and output encoding of shortcode preview content. According to ATT&CK framework, this represents technique T1059.001 Command and Scripting Interpreter: PowerShell and T1546.001 Registry Run Keys / Startup Folder, as attackers could potentially establish persistence through the executed malicious scripts. Organizations should ensure all WordPress installations are updated to version 5.2.3 or later to mitigate this risk, and implement additional security measures such as role-based access controls and monitoring of administrative activities. The vulnerability demonstrates the importance of proper input validation in web applications and highlights how seemingly benign features like preview functionality can become attack vectors when not properly secured. This issue is particularly relevant for WordPress installations that allow multiple user roles with editing capabilities, as it shows how privilege escalation can occur through seemingly innocuous administrative features. The fix implemented by WordPress developers involved enhancing the sanitization process for shortcode previews and ensuring that all user-generated content is properly escaped before being rendered in the browser context.