Index: wp-admin/includes/template.php
===================================================================
--- wp-admin/includes/template.php	(revision 14123)
+++ wp-admin/includes/template.php	(working copy)
@@ -3491,6 +3491,12 @@
 if ( get_user_setting('mfold') == 'f' )
 	$admin_body_class .= ' folded';
 ?>
+<style type="text/css">
+/* fix for scrollbar in iframe*/
+html, body {
+height: 98%; 
+}
+</style>
 </head>
 <body<?php if ( isset($GLOBALS['body_id']) ) echo ' id="' . $GLOBALS['body_id'] . '"'; ?>  class="wp-admin no-js<?php echo apply_filters( 'admin_body_class', '' ) . " $admin_body_class"; ?>">
 <script type="text/javascript">
Index: wp-admin/update-core.php
===================================================================
--- wp-admin/update-core.php	(revision 14123)
+++ wp-admin/update-core.php	(working copy)
@@ -418,7 +418,7 @@
 	echo '<div class="wrap">';
 	screen_icon('plugins');
 	echo '<h2>' . esc_html__('Update Plugins') . '</h2>';
-	echo "<iframe src='$url' style='width: 100%; height:100%; min-height:850px;'></iframe>";
+	echo "<iframe src='$url' style='width: 100%; height:100%; min-height:500px' frameborder='0'></iframe>";
 	echo '</div>';
 } elseif ( 'do-theme-upgrade' == $action ) {
 	check_admin_referer('upgrade-core');
@@ -441,7 +441,7 @@
 	echo '<div class="wrap">';
 	screen_icon('themes');
 	echo '<h2>' . esc_html__('Update Themes') . '</h2>';
-	echo "<iframe src='$url' style='width: 100%; height:100%; min-height:850px;'></iframe>";
+	echo "<iframe src='$url' style='width: 100%; height:100%; min-height:500px;' frameborder='0'></iframe>";
 	echo '</div>';
 }