Index: wp-admin/user-edit.php
===================================================================
--- wp-admin/user-edit.php	(revision 36401)
+++ wp-admin/user-edit.php	(working copy)
@@ -134,7 +134,7 @@
 if ( is_multisite() ) {
 	$user = get_userdata( $user_id );
 
-	if ( $user->user_login && isset( $_POST[ 'email' ] ) && is_email( $_POST[ 'email' ] ) && $wpdb->get_var( $wpdb->prepare( "SELECT user_login FROM {$wpdb->signups} WHERE user_login = %s", $user->user_login ) ) ) {
+	if ( $user->user_login && isset( $_POST[ 'email' ] ) && is_email( wp_unslash( $_POST[ 'email' ] ) ) && $wpdb->get_var( $wpdb->prepare( "SELECT user_login FROM {$wpdb->signups} WHERE user_login = %s", $user->user_login ) ) ) {
 		$wpdb->query( $wpdb->prepare( "UPDATE {$wpdb->signups} SET user_email = %s WHERE user_login = %s", $_POST[ 'email' ], $user_login ) );
 	}
 }