The Slider, Gallery, and Carousel by MetaSlider WordPress plugin before 3.27.9 does not sanitise and escape some of its Gallery Image parameters, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)

The Slider, Gallery, and Carousel by MetaSlider WordPress plugin 3.29.0 does not sanitise and escape a parameter before outputting it back in the page, leading to a Reflected Cross-Site Scripting which could be used against high privilege users such as admin

The Slider, Gallery, and Carousel by MetaSlider – Responsive WordPress Slideshows plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'metaslider' shortcode in all versions up to, and including, 3.70.0 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Slider, Gallery, and Carousel by MetaSlider plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘aria-label’ parameter in all versions up to, and including, 3.98.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.