Ticket #44601: 44601.diff

src/wp-includes/user.php

@@ -2223 +2223 @@
         }
 
         /**
+        * Validating input.
+        *
+        * @since 4.9.7
+        *
+        * @param WP_User $user.
+        */
+        
+        if (  empty( $user ) && !isset( $user ) ) {
+                return new WP_Error( 'no_password_reset', __( 'Error creating password reset key' ) ); 
+        } 
+        
+        if ( $user instanceof WP_User === false ) {
+                return new WP_Error( 'no_password_reset', __( 'Error creating password reset key') );
+        }
+
+        /**
          * Filters whether to allow a password to be reset.
          *
          * @since 2.7.0