Index: src/wp-admin/includes/media.php
===================================================================
--- src/wp-admin/includes/media.php	(revision 27167)
+++ src/wp-admin/includes/media.php	(working copy)
@@ -224,7 +224,7 @@
 <script type="text/javascript">
 /* <![CDATA[ */
 var win = window.dialogArguments || opener || parent || top;
-win.send_to_editor('<?php echo addslashes($html); ?>');
+win.send_to_editor(<?php echo json_encode( $html ); ?>);
 /* ]]> */
 </script>
 <?php