The Master Slider – Responsive Touch Slider WordPress plugin versions up to 3.9.10 contain a stored cross-site scripting vulnerability due to improper neutralization of input in the 'css_id' attribute of the 'ms_layer' shortcode. Authenticated users with contributor or higher privileges can inject arbitrary JavaScript that executes in the context of any user viewing the compromised page. This vulnerability is tracked as CVE-2024-4375 with a CVSS 3.1 base score of 6.4, indicating a medium severity impact. No patch or official remediation guidance is currently available from the vendor, and no exploits have been observed in the wild.

Successful exploitation allows an authenticated contributor-level or higher user to inject persistent malicious scripts into pages using the vulnerable shortcode. This can lead to limited confidentiality and integrity impacts, such as session hijacking or content manipulation, when other users access the infected pages. There is no impact on availability reported. The vulnerability requires authenticated access, reducing the attack surface compared to unauthenticated XSS.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict contributor-level access to trusted users only and consider disabling or removing the Master Slider plugin if possible. Monitor for plugin updates that address this vulnerability.