CVE-2024-4470 is a stored Cross-Site Scripting vulnerability identified in the Master Slider – Responsive Touch Slider plugin for WordPress, versions up to and including 3.9.9. The vulnerability stems from improper neutralization of input (CWE-79) specifically in the 'ms_slide_info' shortcode's 'tag_name' attribute. The plugin fails to adequately sanitize and escape user-supplied input, allowing an attacker with contributor-level or higher privileges to inject arbitrary JavaScript code into pages. Because this is stored XSS, the malicious script is saved in the site's content and executed in the context of any user who views the affected page, potentially compromising user sessions, stealing cookies, or performing actions on behalf of users. The attack vector requires network access and authenticated privileges but no user interaction. The vulnerability has a CVSS v3.1 base score of 6.4 (AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N), reflecting medium severity with low attack complexity and partial impact on confidentiality and integrity. No patches or exploits are currently publicly available, but the vulnerability is publicly disclosed as of May 21, 2024.

The primary impact of this vulnerability is the potential for attackers with contributor-level access to inject persistent malicious scripts into WordPress sites using the affected plugin. This can lead to session hijacking, unauthorized actions performed on behalf of users, defacement, or distribution of malware. Since the vulnerability affects a popular WordPress plugin used globally, compromised sites could suffer reputational damage and loss of user trust. The scope includes all users who visit the infected pages, including administrators and visitors, increasing the risk of widespread compromise. Although exploitation requires authenticated access, many WordPress sites allow contributor-level roles for multiple users or third-party collaborators, increasing the attack surface. The vulnerability does not impact availability directly but can degrade site integrity and confidentiality significantly.

1. Immediately update the Master Slider plugin to a patched version once available from the vendor. 2. Until a patch is released, restrict contributor-level and higher privileges to trusted users only and audit existing user roles to minimize risk. 3. Implement Web Application Firewall (WAF) rules to detect and block attempts to inject scripts via the 'ms_slide_info' shortcode parameters. 4. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected sites. 5. Regularly scan WordPress sites for injected scripts or unusual shortcode usage. 6. Educate site administrators and contributors about the risks of XSS and safe content management practices. 7. Consider disabling or removing the Master Slider plugin if it is not essential until a secure version is available.