CVE-2024-11889 is a stored Cross-Site Scripting (XSS) vulnerability identified in the My IDX Home Search plugin for WordPress, which is widely used for real estate IDX (Internet Data Exchange) home search functionality. The vulnerability exists due to insufficient sanitization and escaping of user-supplied attributes in the 'homeasap-idx-search' shortcode. Specifically, authenticated users with contributor-level access or higher can inject arbitrary JavaScript code into pages via shortcode attributes. Because this is stored XSS, the malicious script persists in the website's content and executes in the browsers of any visitors who load the infected page. This can lead to theft of cookies, session tokens, or other sensitive information, unauthorized actions on behalf of users, or redirection to malicious sites. The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N) indicates that the attack can be launched remotely over the network with low attack complexity, requires privileges (contributor or higher), no user interaction is needed, and the vulnerability affects confidentiality and integrity with a scope change (potentially affecting other users). No patches are currently linked, and no active exploitation has been reported, but the vulnerability is publicly disclosed as of December 14, 2024. The plugin’s widespread use in WordPress sites, especially those related to real estate, increases the potential attack surface. The vulnerability highlights the importance of rigorous input validation and output encoding in WordPress plugin development to prevent injection flaws.

The primary impact of CVE-2024-11889 is the compromise of confidentiality and integrity on affected WordPress sites using the My IDX Home Search plugin. Attackers with contributor-level access can inject persistent malicious scripts that execute in the browsers of site visitors and administrators. This can lead to session hijacking, credential theft, unauthorized actions performed with victim privileges, defacement, or distribution of malware. For organizations, this can result in reputational damage, loss of customer trust, and potential regulatory consequences if sensitive user data is exposed. Since contributors are typically trusted users, the vulnerability also enables insider threat escalation. The scope change means the attacker can affect other users beyond their own privileges. Although availability is not directly impacted, the indirect effects of injected scripts can disrupt normal site operations. The vulnerability is particularly concerning for real estate businesses relying on IDX search functionality, as attackers could manipulate listings or redirect users to fraudulent sites. Given the medium CVSS score and the requirement for authenticated access, the risk is moderate but significant for organizations with multiple contributors or less strict access controls.

To mitigate CVE-2024-11889, organizations should first update the My IDX Home Search plugin to a version that addresses this vulnerability once available. In the absence of an official patch, administrators should restrict contributor-level access to trusted users only and review existing contributor accounts for suspicious activity. Implementing additional input validation and output escaping at the shortcode processing level can help prevent malicious script injection. Employ Web Application Firewalls (WAFs) with rules targeting XSS payloads in shortcode attributes. Regularly audit site content for unexpected or suspicious shortcode usage. Educate contributors about safe content practices and the risks of injecting untrusted code. Additionally, enable Content Security Policy (CSP) headers to reduce the impact of injected scripts by restricting script sources. Monitoring logs for unusual shortcode parameter values and user behavior can provide early detection of exploitation attempts. Finally, consider isolating or sandboxing user-generated content areas to limit script execution scope.