The WordPress WP YouTube Live Plugin is vulnerable to Reflected Cross-Site Scripting via POST data found in the ~/inc/admin.php file which allows unauthenticated attackers to inject arbitrary web scripts in versions up to, and including, 1.7.21.
https://plugins.trac.wordpress.org/browser/wp-youtube-live/trunk/inc/admin.php#L355
https://github.com/macbookandrew/wp-youtube-live/commit/2d8ccb7b12742bf16b5a6068f9fdeeac69bc11b1