diff --git a/grub-core/net/tftp.c b/grub-core/net/tftp.c
index 7e659a78b..1f3793ed8 100644
--- a/grub-core/net/tftp.c
+++ b/grub-core/net/tftp.c
@@ -442,6 +442,7 @@ tftp_close (struct grub_file *file)
       grub_net_udp_close (data->sock);
     }
   grub_free (data);
+  file->data = NULL;
   return GRUB_ERR_NONE;
 }