CVE-2024-3890 identifies a stored Cross-Site Scripting (XSS) vulnerability in the Happy Addons for Elementor plugin for WordPress, specifically through the Calendly widget component. This vulnerability exists in all versions up to 3.10.5 due to improper neutralization of input during web page generation, classified under CWE-79. The root cause is insufficient sanitization and escaping of user-supplied attributes, allowing authenticated users with contributor-level or higher privileges 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 performed on behalf of the victim. The vulnerability requires no user interaction beyond visiting the compromised page but does require authentication with contributor or higher privileges, limiting exploitation to insiders or compromised accounts. The CVSS 3.1 base score is 6.4, indicating a medium severity with network attack vector, low attack complexity, and privileges required. The scope is changed (S:C), meaning the vulnerability can affect resources beyond the vulnerable component. No public exploits are currently known, but the risk remains significant given the widespread use of Elementor and its add-ons in WordPress sites. The vulnerability highlights the importance of proper input validation and output encoding in web applications, especially those that allow user-generated content or attributes.

The impact of CVE-2024-3890 on organizations worldwide includes potential compromise of user sessions, unauthorized actions performed with victim privileges, defacement of websites, and possible data leakage through malicious scripts. Since the vulnerability is stored XSS, injected scripts persist and affect all users who visit the compromised pages, amplifying the attack surface. Organizations using the Happy Addons for Elementor plugin risk reputational damage, loss of customer trust, and potential regulatory consequences if user data is exposed or manipulated. The requirement for contributor-level access limits exploitation to insiders or attackers who have already compromised accounts, but this does not eliminate risk, especially in environments with multiple content editors or weak access controls. The vulnerability does not impact availability directly but can indirectly cause service disruptions if exploited to inject malicious payloads or redirect users. Given the popularity of WordPress and Elementor, many websites globally could be affected, including corporate, e-commerce, and media sites, increasing the potential scale of impact.

To mitigate CVE-2024-3890, organizations should immediately update the Happy Addons for Elementor plugin to a patched version once available. Until a patch is released, restrict contributor-level and higher access to trusted users only, and audit existing user accounts for suspicious activity. Implement Web Application Firewall (WAF) rules to detect and block malicious payloads targeting the Calendly widget or suspicious script injections. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected pages. Regularly scan WordPress sites for XSS vulnerabilities and malicious content injections using specialized security plugins or external scanning tools. Educate content editors and administrators about the risks of injecting untrusted content and enforce strict input validation policies. Monitor logs for unusual activity related to page edits or script injections. Finally, consider isolating or disabling the Calendly widget feature if it is not essential, reducing the attack surface.