diff --git a/src/config/nm-config-device.c b/src/config/nm-config-device.c
index b68723e3b2..62c1efedd0 100644
--- a/src/config/nm-config-device.c
+++ b/src/config/nm-config-device.c
@@ -73,7 +73,7 @@ char *
 nm_config_device_get_hwaddr (NMConfigDevice *self)
 {
 	const guint8 *bytes;
-	guint len;
+	guint len = 0;
 
 	bytes = NM_CONFIG_DEVICE_GET_INTERFACE (self)->get_hw_address (self, &len);
 	return nm_utils_hwaddr_ntoa (bytes, nm_utils_hwaddr_type (len));