diff --git a/src/kdc/do_as_req.c b/src/kdc/do_as_req.c
index 46b5fa1..464cb6e 100644
--- a/src/kdc/do_as_req.c
+++ b/src/kdc/do_as_req.c
@@ -741,6 +741,8 @@ prepare_error_as (struct kdc_request_state *rstate, krb5_kdc_req *request,
                     pad->contents = td[size]->data;
                     pad->length = td[size]->length;
                     pa[size] = pad;
+                    td[size]->data = NULL;
+                    td[size]->length = 0;
                 }
             krb5_free_typed_data(kdc_context, td);
         }