Hardening: Remove the ability to upload JavaScript files for users who do not have the `unfiltered_html` capability.

Merges [42261] to the 4.9 branch.

Built from https://develop.svn.wordpress.org/branches/4.9@42267


git-svn-id: http://core.svn.wordpress.org/branches/4.9@42096 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/functions.php

@@ -2561,8 +2561,9 @@ function get_allowed_mime_types( $user = null ) {
 	if ( function_exists( 'current_user_can' ) )
 		$unfiltered = $user ? user_can( $user, 'unfiltered_html' ) : current_user_can( 'unfiltered_html' );
 
-	if ( empty( $unfiltered ) )
-		unset( $t['htm|html'] );
+	if ( empty( $unfiltered ) ) {
+		unset( $t['htm|html'], $t['js'] );
+	}
 
 	/**
 	 * Filters list of allowed mime types and file extensions.

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9.1-beta1-42266';
+$wp_version = '4.9.1-beta1-42267';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.