CVE-2024-4156 is a stored cross-site scripting vulnerability identified in the Essential Addons for Elementor plugin for WordPress, specifically affecting versions up to and including 5.9.17. The vulnerability stems from improper neutralization of input during web page generation, classified under CWE-79. The affected parameter, 'eael_event_text_color', does not undergo sufficient input sanitization or output escaping, enabling an authenticated attacker with contributor-level or higher permissions to inject arbitrary JavaScript code into pages. Because the malicious script is stored persistently, it executes every time a user accesses the infected page, potentially compromising user sessions, stealing cookies, or performing unauthorized actions within the context of the victim's browser session. The vulnerability has a CVSS v3.1 base score of 6.4, reflecting medium severity, with an attack vector of network, low attack complexity, requiring privileges (PR:L), no user interaction, and scope change (S:C). The scope change indicates that the vulnerability affects resources beyond the initially vulnerable component, potentially impacting other parts of the application or user data. No public exploits have been reported yet, but the vulnerability poses a significant risk due to the widespread use of the plugin in WordPress sites, including those running WooCommerce and other e-commerce functionalities. The vulnerability was reserved on April 24, 2024, and published on May 2, 2024, by Wordfence. No official patches or updates are linked yet, so mitigation may require manual intervention or disabling the vulnerable plugin until a fix is released.

The primary impact of CVE-2024-4156 is the compromise of confidentiality and integrity of user sessions and data on affected WordPress sites. Attackers with contributor-level access can inject persistent malicious scripts that execute in the browsers of any user visiting the infected pages. This can lead to session hijacking, unauthorized actions performed on behalf of users, defacement, or distribution of malware. For e-commerce sites using WooCommerce with this plugin, the risk extends to theft of customer data, manipulation of transactions, or reputational damage. The vulnerability does not directly affect availability but can indirectly cause service disruptions if exploited for defacement or malware distribution. Given the plugin’s popularity, a large number of WordPress sites globally are at risk, especially those that allow contributor-level user roles. The requirement for authenticated access limits exploitation to insiders or compromised accounts, but the ease of exploitation and lack of user interaction make it a notable threat. Organizations failing to address this vulnerability may face data breaches, loss of customer trust, and regulatory consequences depending on the data involved.

To mitigate CVE-2024-4156, organizations should immediately assess their WordPress installations for the presence of the Essential Addons for Elementor plugin, particularly versions up to 5.9.17. Until an official patch is released, consider the following specific actions: 1) Restrict contributor-level permissions to trusted users only, minimizing the risk of malicious script injection. 2) Implement a Web Application Firewall (WAF) with custom rules to detect and block suspicious input patterns targeting the 'eael_event_text_color' parameter. 3) Regularly audit and sanitize content submitted by contributors, especially any input fields related to event text color or similar parameters. 4) Monitor website pages for unexpected script injections or changes in page content. 5) Disable or remove the vulnerable plugin if it is not essential or if no timely patch is available. 6) Prepare to update the plugin promptly once a security update is released by the vendor. 7) Educate site administrators and contributors about the risks of XSS and the importance of secure content handling. These targeted steps go beyond generic advice by focusing on access control, input validation, and proactive monitoring specific to this vulnerability’s context.