CVE-2024-5020 is a stored Cross-Site Scripting (XSS) vulnerability identified in the Colibri Page Builder plugin for WordPress, developed by extendthemes. The root cause is the improper neutralization of input during web page generation, specifically due to insufficient sanitization and escaping of user-supplied attributes in the plugin's bundled FancyBox JavaScript library versions 1.3.4 through 3.5.7. This vulnerability allows authenticated attackers with contributor-level or higher privileges to inject arbitrary JavaScript code into pages managed by the plugin. Because the malicious scripts are stored persistently, they execute automatically whenever any user accesses the infected page, without requiring additional user interaction. The CVSS v3.1 score of 6.4 reflects a medium severity, with the vector indicating network attack vector, low attack complexity, privileges required (low), no user interaction, and a scope change. The impact primarily affects confidentiality and integrity, enabling potential session hijacking, credential theft, or unauthorized actions performed in the context of the victim’s browser session. Although no public exploits are currently known, the widespread use of WordPress and the popularity of page builder plugins make this a significant risk. The vulnerability affects all versions of the Colibri Page Builder plugin, emphasizing the need for immediate attention from site administrators and developers. The absence of an official patch link suggests that mitigation may currently rely on workarounds or updates from the vendor.

The impact of CVE-2024-5020 is significant for organizations using the Colibri Page Builder plugin on WordPress sites, especially those with multiple contributors or editors. Successful exploitation can lead to the injection of malicious scripts that execute in the browsers of site visitors or administrators, potentially resulting in session hijacking, theft of sensitive information such as authentication tokens or cookies, unauthorized actions performed on behalf of users, and defacement or manipulation of website content. This undermines the confidentiality and integrity of the affected websites and their users. While availability is not directly impacted, the reputational damage and loss of user trust can have substantial business consequences. The vulnerability is exploitable remotely over the network by authenticated users with relatively low privileges, increasing the risk in environments where contributor access is granted to multiple users. Given WordPress’s global market share and the popularity of page builder plugins, the threat extends to a broad range of sectors including media, e-commerce, education, and government websites. The lack of known exploits in the wild currently reduces immediate risk but does not preclude future attacks, especially as threat actors often target such vulnerabilities once disclosed.

To mitigate CVE-2024-5020, organizations should take the following specific actions: 1) Immediately check for updates or patches from extendthemes for the Colibri Page Builder plugin and apply them as soon as they become available. 2) If no official patch exists, consider temporarily disabling the plugin or restricting contributor-level access until a fix is released. 3) Implement strict input validation and output encoding on all user-supplied data within the plugin’s scope, particularly focusing on attributes processed by the FancyBox library. 4) Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious script injection attempts targeting the affected plugin. 5) Review and minimize the number of users with contributor or higher privileges to reduce the attack surface. 6) Conduct regular security audits and scanning for XSS vulnerabilities on WordPress sites using automated tools that can detect stored XSS. 7) Educate content contributors about the risks of injecting untrusted content and enforce content moderation policies. 8) Monitor website logs and user activity for unusual behavior indicative of exploitation attempts. 9) Consider implementing Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts. These measures, combined, will reduce the likelihood and impact of exploitation until a vendor patch is available.