diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 29877465cf3..59d730cf0b7 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -671,6 +671,7 @@ BUILD_FUNC_DEF_2(PySocketSock_getsockname,PySocketSockObject *,s, PyObject *,arg
 		return NULL;
 	if (!getsockaddrlen(s, &addrlen))
 		return NULL;
+	memset(addrbuf, 0, addrlen);
 	Py_BEGIN_ALLOW_THREADS
 	res = getsockname(s->sock_fd, (struct sockaddr *) addrbuf, &addrlen);
 	Py_END_ALLOW_THREADS