CVE-2024-50470 in YouTube External Subtitles Plugin
Summary
by MITRE • 10/28/2024
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Themes4WP Themes4WP YouTube External Subtitles themes4wp-youtube-external-subtitles allows DOM-Based XSS.This issue affects Themes4WP YouTube External Subtitles: from n/a through <= 1.0.
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Analysis
by VulDB Data Team • 04/06/2026
This vulnerability represents a critical cross-site scripting flaw that specifically targets the web page generation process within the Themes4WP YouTube External Subtitles WordPress plugin. The issue manifests as a DOM-based XSS attack, which means the malicious script is executed within the victim's browser through manipulation of the Document Object Model rather than traditional server-side input handling. The vulnerability exists in the plugin's handling of user-supplied input during the dynamic generation of web pages, creating an attack surface where malicious JavaScript code can be injected and executed in the context of legitimate user sessions.
The technical flaw stems from inadequate input sanitization and output escaping mechanisms within the plugin's codebase. When the plugin processes external subtitle data or user parameters for display on web pages, it fails to properly neutralize potentially malicious input before incorporating it into the DOM structure. This allows attackers to craft malicious payloads that, when executed, can hijack user sessions, steal sensitive cookies, perform unauthorized actions on behalf of users, or redirect victims to malicious websites. The vulnerability affects all versions of the plugin up to and including version 1.0, indicating a persistent flaw that has not been addressed in the affected release cycle.
The operational impact of this vulnerability is significant for WordPress site administrators and users who employ the affected plugin. Attackers can exploit this flaw by crafting malicious URLs or embedding malicious content that, when viewed by unsuspecting users, executes the injected scripts within their browser context. This creates a persistent threat vector that can be leveraged for session hijacking, credential theft, or as a stepping stone for more sophisticated attacks. The DOM-based nature of the vulnerability means that traditional server-side input validation measures may not prevent exploitation, requiring more comprehensive client-side security controls. The vulnerability directly relates to CWE-79 which classifies cross-site scripting flaws, and aligns with ATT&CK technique T1566.001 for initial access through malicious content.
Mitigation strategies should focus on immediate remediation through plugin updates to the latest version where the vulnerability has been patched. Site administrators must also implement additional security measures including Content Security Policy (CSP) headers to restrict script execution, proper input validation and sanitization at multiple layers, and regular security audits of installed plugins. Network-level protections such as web application firewalls can provide additional defense-in-depth, while user education regarding suspicious links and content remains crucial. Organizations should also consider implementing automated vulnerability scanning tools to identify similar issues in other third-party components and maintain comprehensive backup strategies to quickly restore systems if exploitation occurs.