diff --git a/util/tube.c b/util/tube.c
index 7d98b93c3..96187e134 100644
--- a/util/tube.c
+++ b/util/tube.c
@@ -584,7 +584,10 @@ void tube_close_write(struct tube* ATTR_UNUSED(tube))
 void tube_remove_bg_listen(struct tube* tube)
 {
 	verbose(VERB_ALGO, "tube remove_bg_listen");
-	ub_winsock_unregister_wsaevent(tube->ev_listen);
+	if (tube->ev_listen != NULL) {
+		ub_winsock_unregister_wsaevent(tube->ev_listen);
+		tube->ev_listen = NULL;
+	}
 }
 
 void tube_remove_bg_write(struct tube* tube)