diff --git a/phpseclib/Net/SSH2.php b/phpseclib/Net/SSH2.php
index bc718c8a..94143a99 100644
--- a/phpseclib/Net/SSH2.php
+++ b/phpseclib/Net/SSH2.php
@@ -2892,7 +2892,7 @@ class Net_SSH2
         if (($this->bitmap & NET_SSH2_MASK_CONNECTED) && ($this->bitmap & NET_SSH2_MASK_LOGIN)) {
             switch (ord($payload[0])) {
                 case NET_SSH2_MSG_GLOBAL_REQUEST: // see http://tools.ietf.org/html/rfc4254#section-4
-                    extract(unpack('Nlength', $this->_string_shift($payload)));
+                    extract(unpack('Nlength', $this->_string_shift($payload, 4)));
                     $this->errors[] = 'SSH_MSG_GLOBAL_REQUEST: ' . $this->_string_shift($payload, $length);
 
                     if (!$this->_send_binary_packet(pack('C', NET_SSH2_MSG_REQUEST_FAILURE))) {