The plugin contains a CSRF vulnerability which allows an attacker to change any setting in the plugin so long as they can cause a logged-in admin user to follow a link.
The impact of the CSRF vulnerability appears to be limited because it seems that the plugin is not vulnerable to XSS or anything else which could be used in conjunction with the CSRF vulnerability.
Proof of concept
Visit a page with the following content, and click submit:
<form method="POST" action="http://localhost/wp-admin/admin.php?page=youtube-my-preferences"> <input type="text" name="ytprefs_submitted" value="Y"> <input type="text" name="apikey" value="HELLO"> <input type="submit"> </form>
The “YouTube API Key:” value will be set to “HELLO”.
In a real attack, forms can be auto-submitted.
Upgrade to version 11.8.2 or later.