diff --git a/wp-includes/class-IXR.php b/wp-includes/class-IXR.php
index c4d447743..380301248 100644
--- a/wp-includes/class-IXR.php
+++ b/wp-includes/class-IXR.php
@@ -216,6 +216,7 @@ class IXR_Message
         xml_set_element_handler($this->_parser, 'tag_open', 'tag_close');
         xml_set_character_data_handler($this->_parser, 'cdata');
         $chunk_size = 262144; // 256Kb, parse in chunks to avoid the RAM usage on very large messages
+        $final = false;
         do {
             if (strlen($this->message) <= $chunk_size) {
                 $final = true;