Index: wp-includes/js/tinymce/plugins/wordpress/editor_plugin_src.js
===================================================================
--- wp-includes/js/tinymce/plugins/wordpress/editor_plugin_src.js	(revision 23141)
+++ wp-includes/js/tinymce/plugins/wordpress/editor_plugin_src.js	(working copy)
@@ -138,7 +138,7 @@
 			// Extend <object> and <embed> (#WP22790)
 			ed.onPreInit.add(function(ed) {
 				ed.schema.addValidElements('object[*],param[id|name|value|valuetype|type],embed[*]');
-				ed.schema.addValidChildren('object[*]');
+				ed.schema.addValidChildren('+object[embed]');
 			});
 
 			ed.onInit.add(function(ed) {