CVE-2025-4099 in List Children
Summary
by MITRE • 05/01/2025
The List Children plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'list_children' shortcode in all versions up to, and including, 2.1 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 05/19/2025
The CVE-2025-4099 vulnerability affects the List Children plugin for WordPress, a widely used tool for displaying hierarchical content structures on websites. This plugin enables administrators to create nested lists of posts, pages, or custom post types, making it a common component in WordPress installations. The vulnerability exists in all versions up to and including 2.1, representing a significant security risk for WordPress sites that rely on this functionality. The issue stems from inadequate input validation and output escaping mechanisms within the plugin's shortcode implementation, specifically the 'list_children' shortcode which is designed to render hierarchical content dynamically.
The technical flaw manifests through the plugin's insufficient sanitization of user-supplied attributes passed to the list_children shortcode. When administrators or authorized users provide parameters to this shortcode, the plugin fails to properly validate or escape these inputs before rendering them in the output HTML. This vulnerability falls under CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a core category for cross-site scripting flaws. The vulnerability is particularly concerning because it requires only contributor-level access, making it accessible to users who should not have the ability to inject malicious code into the website. This low privilege requirement significantly increases the attack surface and potential impact of exploitation.
The operational impact of this vulnerability extends beyond simple script execution, as it creates a persistent threat vector that can affect all users who access pages containing the maliciously injected content. An authenticated attacker with contributor privileges can insert malicious JavaScript code into the shortcode parameters, which will then execute in the context of any user who views pages containing the affected shortcode. This stored XSS vulnerability allows for various attack vectors including session hijacking, credential theft, defacement of content, and redirection to malicious sites. The attack chain begins with privilege escalation to contributor level, followed by injection of malicious payloads through the plugin's shortcode interface, and concludes with execution of these scripts in the browsers of unsuspecting visitors. This vulnerability directly maps to ATT&CK technique T1566.001 - Phishing: Spearphishing Attachment, as it enables attackers to create malicious content that can be delivered to users through legitimate website pages.
Mitigation strategies for CVE-2025-4099 should prioritize immediate plugin updates to versions that address the sanitization issues. System administrators should also implement additional security measures such as restricting contributor-level access to only essential plugin functionalities and monitoring user activities for suspicious shortcode usage patterns. Input validation should be strengthened at multiple layers including server-side validation of all shortcode attributes and proper HTML escaping of dynamic content. Organizations should consider implementing content security policies to limit script execution capabilities and conduct regular security audits of installed plugins to identify similar vulnerabilities. The vulnerability demonstrates the critical importance of input sanitization and output escaping in web applications, particularly those with user-facing content management capabilities. Regular security assessments and prompt patch management are essential for maintaining WordPress site integrity against such persistent threats.