Slider Hero < 9.1.3 - Unauthenticated Stored XSS via Slider Type Change and Add-Slider Handlers

Description

The plugin does not have authorisation and nonce checks on two of its request handlers, and does not escape a stored setting before outputting it, allowing unauthenticated users to store malicious JavaScript which will be executed in the context of an administrator viewing the plugin's admin area, as well as any visitor of a page embedding a slider.