diff --git a/openbsc/src/nat/bsc_mgcp_utils.c b/openbsc/src/nat/bsc_mgcp_utils.c
index 0965f1f..164b6f6 100644
--- a/openbsc/src/nat/bsc_mgcp_utils.c
+++ b/openbsc/src/nat/bsc_mgcp_utils.c
@@ -148,7 +148,7 @@
 		talloc_free(bsc_endp->transaction_id);
 	}
 
-	bsc_endp->transaction_id = talloc_strdup(bsc_endp, transaction_id);
+	bsc_endp->transaction_id = talloc_strdup(nat, transaction_id);
 	bsc_endp->bsc = bsc_con;
 
 	/* we need to update some bits */