CVE-2024-6158 in Category Posts Widget Plugin
Summary
by MITRE • 08/12/2024
The Category Posts Widget WordPress plugin before 4.9.17, term-and-category-based-posts-widget WordPress plugin before 4.9.13 does not validate and escape some of its "Category Posts" widget settings before outputting them back in a page/post where the Widget is embed, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)
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Analysis
by VulDB Data Team • 03/15/2025
The vulnerability identified as CVE-2024-6158 affects two popular WordPress plugins: Category Posts Widget and term-and-category-based-posts-widget. These plugins are designed to display posts based on specific categories or terms, making them widely used across WordPress installations. The flaw resides in the improper handling of user input within the widget settings, specifically failing to validate and escape certain parameters before rendering them back into web pages. This represents a critical security oversight that undermines the fundamental principles of input sanitization and output escaping that are essential for preventing cross-site scripting attacks. The vulnerability is particularly concerning because it affects high-privilege users including administrators who can leverage this weakness even in environments where the unfiltered_html capability has been restricted, such as in multisite WordPress configurations where security hardening is typically more stringent.
The technical implementation of this vulnerability stems from a failure to properly sanitize user-provided data within the widget configuration interface. When administrators configure the category posts widget, they can input various parameters including category IDs, post counts, and display options. However, the plugins do not adequately validate or escape these inputs before storing and subsequently outputting them in the frontend. This creates a stored cross-site scripting scenario where malicious scripts can be injected and persistently executed whenever the widget is rendered on a webpage. The vulnerability is categorized under CWE-79, which specifically addresses Cross-Site Scripting flaws, and aligns with ATT&CK technique T1548.005 related to Abuse of Functionality. The weakness occurs because the plugins fail to implement proper input validation mechanisms and output escaping routines that would prevent malicious payloads from being executed in the context of other users' browsers. The attack vector is particularly dangerous in multisite environments where administrators might believe that restricted capabilities provide adequate protection, but the vulnerability allows them to bypass these restrictions through the widget functionality.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, data exfiltration, and privilege escalation within the WordPress environment. An attacker with administrator access can inject malicious JavaScript code that could steal cookies, redirect users to phishing sites, or even modify content on the website. In multisite configurations, where security policies are often more rigid, this vulnerability becomes even more dangerous as it allows attackers to circumvent the intended security measures. The stored nature of the XSS means that the malicious code persists in the database and executes every time the widget is displayed, potentially affecting all users who view pages containing the compromised widget. This vulnerability directly violates the principle of least privilege and can lead to complete compromise of the WordPress installation, especially when combined with other attack vectors or when administrators have elevated permissions that allow them to modify core functionality.
Mitigation strategies for CVE-2024-6158 should focus on immediate plugin updates to versions 4.9.17 and 4.9.13 respectively, which contain the necessary patches to address the input validation and output escaping deficiencies. Organizations should also implement additional security measures including regular security audits of installed plugins, monitoring for unauthorized changes to widget configurations, and implementing content security policies to limit the impact of potential XSS attacks. Security teams should conduct thorough vulnerability assessments to identify any other plugins or themes that might exhibit similar weaknesses in input handling and output escaping. The remediation process should include not only updating the vulnerable plugins but also reviewing and hardening the WordPress security configuration, particularly in multisite environments where the attack surface is expanded. Network security controls such as web application firewalls and intrusion detection systems should be configured to monitor for suspicious widget configurations and malicious script injections. Regular security training for administrators is essential to ensure they understand the importance of plugin security and the risks associated with storing unvalidated user input in web applications. The vulnerability highlights the critical need for robust input validation and output escaping mechanisms in all web applications, particularly those that handle user-provided content in dynamic environments.