CVE-2024-4356 is a stored Cross-Site Scripting (XSS) vulnerability identified in the 'List categories' WordPress plugin developed by fernandobt. This vulnerability affects all versions up to and including 0.4. The root cause is insufficient sanitization and escaping of user-supplied input in the 'categories' shortcode, which allows authenticated users with contributor-level permissions or higher to inject arbitrary JavaScript code into pages. When other users access these pages, the injected scripts execute in their browsers, potentially leading to session hijacking, privilege escalation, or unauthorized actions within the context of the vulnerable site. The vulnerability is classified under CWE-79, indicating improper neutralization of input during web page generation. The CVSS v3.1 base score is 6.4, reflecting a medium severity with network attack vector, low attack complexity, and requiring privileges but no user interaction. The scope is changed (S:C), meaning the vulnerability affects resources beyond the vulnerable component, impacting confidentiality and integrity but not availability. No patches or known exploits have been reported at the time of publication, but the vulnerability's presence in a widely used CMS plugin makes it a notable risk. The vulnerability is particularly dangerous because contributor-level users are common in WordPress environments, and the stored nature of the XSS means persistent impact on site visitors.

The primary impact of CVE-2024-4356 is the compromise of confidentiality and integrity within affected WordPress sites. Attackers with contributor-level access can inject malicious scripts that execute in the browsers of site visitors and administrators, potentially stealing session cookies, performing actions on behalf of users, or defacing content. This can lead to unauthorized access, data leakage, and erosion of user trust. Since WordPress powers a significant portion of the web, sites using the vulnerable plugin are at risk of targeted attacks, especially if they have multiple contributors. The vulnerability does not affect availability directly but can facilitate further attacks that degrade service or lead to site compromise. Organizations relying on this plugin for content categorization may face reputational damage and regulatory consequences if user data is exposed or manipulated.

To mitigate CVE-2024-4356, organizations should first check for updates from the plugin developer and apply any available patches promptly. In the absence of an official patch, administrators should consider disabling the 'List categories' plugin or removing the vulnerable shortcode from all pages. Implementing strict input validation and output escaping at the application level can reduce risk, such as using WordPress's built-in functions like esc_attr() and esc_html() for sanitization. Restrict contributor-level permissions to trusted users only and monitor user-generated content for suspicious scripts. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts. Regularly audit WordPress plugins for vulnerabilities and maintain a minimal plugin footprint to reduce attack surface. Additionally, security plugins that detect and block XSS attempts can provide an additional layer of defense.