Index: src/wp-includes/js/mce-view.js
===================================================================
--- src/wp-includes/js/mce-view.js	(revision 35197)
+++ src/wp-includes/js/mce-view.js	(working copy)
@@ -732,7 +732,26 @@
  * and a view for embeddable URLs.
  */
 ( function( window, views, media, $ ) {
-	var base, gallery, av, embed;
+	var base, gallery, av, embed,
+		schema, parser, serializer;
+
+	function verifyHTML( string ) {
+		var settings = {};
+
+		if ( ! window.tinymce ) {
+			return string.replace( /<[^>]+>/g, '' );
+		}
+
+		if ( ! string || ( string.indexOf( '<' ) === -1 && string.indexOf( '>' ) === -1 ) ) {
+			return string;
+		}
+
+		schema = schema || new window.tinymce.html.Schema( settings );
+		parser = parser || new window.tinymce.html.DomParser( settings, schema );
+		serializer = serializer || new window.tinymce.html.Serializer( settings, schema );
+
+		return serializer.serialize( parser.parse( string, { forced_root_block: false } ) );
+	}
 
 	base = {
 		state: [],
@@ -783,6 +802,7 @@
 				} );
 
 				self.render( self.template( {
+					verifyHTML: verifyHTML,
 					attachments: attachments,
 					columns: attrs.columns ? parseInt( attrs.columns, 10 ) : media.galleryDefaults.columns
 				} ) );
Index: src/wp-includes/media-template.php
===================================================================
--- src/wp-includes/media-template.php	(revision 35197)
+++ src/wp-includes/media-template.php	(working copy)
@@ -1216,7 +1216,7 @@
 						</dt>
 						<# if ( attachment.caption ) { #>
 							<dd class="wp-caption-text gallery-caption">
-								{{ attachment.caption }}
+								{{{ data.verifyHTML( attachment.caption ) }}}
 							</dd>
 						<# } #>
 					</dl>