diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index 5ac31d1f578..427e2eb7346 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -8014,7 +8014,7 @@ static bool send_server_handshake_packet(MPVIO_EXT *mpvio,
   end= strmake(end, plugin_name(mpvio->plugin)->str,
                     plugin_name(mpvio->plugin)->length);
 
-  int res= my_net_write(mpvio->net, (uchar*) buff, (size_t) (end - buff)) ||
+  int res= my_net_write(mpvio->net, (uchar*) buff, (size_t) (end - buff + 1)) ||
            net_flush(mpvio->net);
   my_afree(buff);
   DBUG_RETURN (res);