Index: src/wp-includes/script-loader.php
===================================================================
--- src/wp-includes/script-loader.php	(revision 36184)
+++ src/wp-includes/script-loader.php	(working copy)
@@ -170,7 +170,7 @@
 	$scripts->add( 'wp-lists', "/wp-includes/js/wp-lists$suffix.js", array( 'wp-ajax-response', 'jquery-color' ), false, 1 );
 
 	// WordPress no longer uses or bundles Prototype or script.aculo.us. These are now pulled from an external source.
-	$scripts->add( 'prototype', 'https://ajax.googleapis.com/ajax/libs/prototype/1.7.1.0/prototype.js', array(), '1.7.1');
+	$scripts->add( 'prototype', 'https://ajax.googleapis.com/ajax/libs/prototype/1.7.3.0/prototype.js', array(), '1.7.3');
 	$scripts->add( 'scriptaculous-root', 'https://ajax.googleapis.com/ajax/libs/scriptaculous/1.9.0/scriptaculous.js', array('prototype'), '1.9.0');
 	$scripts->add( 'scriptaculous-builder', 'https://ajax.googleapis.com/ajax/libs/scriptaculous/1.9.0/builder.js', array('scriptaculous-root'), '1.9.0');
 	$scripts->add( 'scriptaculous-dragdrop', 'https://ajax.googleapis.com/ajax/libs/scriptaculous/1.9.0/dragdrop.js', array('scriptaculous-builder', 'scriptaculous-effects'), '1.9.0');