Index: src/wp-admin/includes/class-wp-ms-users-list-table.php
===================================================================
--- src/wp-admin/includes/class-wp-ms-users-list-table.php	(revision 26288)
+++ src/wp-admin/includes/class-wp-ms-users-list-table.php	(working copy)
@@ -16,7 +16,7 @@
 	function prepare_items() {
 		global $usersearch, $role, $wpdb, $mode;
 
-		$usersearch = isset( $_REQUEST['s'] ) ? $_REQUEST['s'] : '';
+		$usersearch = isset( $_REQUEST['s'] ) ? wp_unslash( trim( $_REQUEST['s'] ) ) : '';
 
 		$users_per_page = $this->get_items_per_page( 'users_network_per_page' );
 
Index: src/wp-admin/includes/class-wp-users-list-table.php
===================================================================
--- src/wp-admin/includes/class-wp-users-list-table.php	(revision 26288)
+++ src/wp-admin/includes/class-wp-users-list-table.php	(working copy)
@@ -35,7 +35,7 @@
 	function prepare_items() {
 		global $role, $usersearch;
 
-		$usersearch = isset( $_REQUEST['s'] ) ? trim( $_REQUEST['s'] ) : '';
+		$usersearch = isset( $_REQUEST['s'] ) ? wp_unslash( trim( $_REQUEST['s'] ) ) : '';
 
 		$role = isset( $_REQUEST['role'] ) ? $_REQUEST['role'] : '';