diff --git a/wp-includes/user.php b/wp-includes/user.php
index 4c14aa6451..d0b760986c 100644
--- a/wp-includes/user.php
+++ b/wp-includes/user.php
@@ -2217,6 +2217,10 @@ function wp_get_password_hint() {
 function get_password_reset_key( $user ) {
 	global $wpdb, $wp_hasher;
 
+	if ( ! ( $user instanceof WP_User ) ) {
+		return new WP_Error( 'invalidcombo', __( '<strong>ERROR</strong>: There is no account with that username or email address.' ) );
+	}
+
 	/**
 	 * Fires before a new password is retrieved.
 	 *
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 038fdf8325..beb08a0cb9 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-beta1-44601';
+$wp_version = '5.1-beta1-44602';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.