diff --git a/spa/plugins/bluez5/modemmanager.c b/spa/plugins/bluez5/modemmanager.c
index 4fa29b082..10310e31b 100644
--- a/spa/plugins/bluez5/modemmanager.c
+++ b/spa/plugins/bluez5/modemmanager.c
@@ -141,9 +141,10 @@ static void mm_get_call_properties_reply(DBusPendingCall *pending, void *user_da
 
 			dbus_message_iter_get_basic(&value_i, &number);
 			spa_log_debug(this->log, "Call number: %s", number);
-			if (call->number)
-				free(call->number);
+			free(call->number);
 			call->number = strdup(number);
+			if (call->number == NULL)
+				return;
 		} else if (spa_streq(key, MM_CALL_PROPERTY_STATE)) {
 			int clcc_state;
 
@@ -363,6 +364,8 @@ static DBusHandlerResult mm_parse_interfaces(struct impl *this, DBusMessageIter
 					}
 				}
 				this->modem.path = strdup(path);
+				if (this->modem.path == NULL)
+					goto next;
 			} else if (!spa_streq(this->modem.path, path)) {
 				spa_log_debug(this->log, "A modem is already registered");
 				goto next;
@@ -618,6 +621,10 @@ static DBusHandlerResult mm_filter_cb(DBusConnection *bus, DBusMessage *m, void
 			return DBUS_HANDLER_RESULT_NEED_MEMORY;
 		call_object->this = this;
 		call_object->path = strdup(path);
+		if (call_object->path == NULL) {
+			free(call_object);
+			return DBUS_HANDLER_RESULT_NEED_MEMORY;
+		}
 		spa_list_append(&this->call_list, &call_object->link);
 
 		m2 = dbus_message_new_method_call(MM_DBUS_SERVICE, path, DBUS_INTERFACE_PROPERTIES, "GetAll");
@@ -1113,8 +1120,11 @@ void *mm_register(struct spa_log *log, void *dbus_connection, const struct spa_d
 	this->conn = dbus_connection;
 	this->ops = ops;
 	this->user_data = user_data;
-	if (modem_device_str && !spa_streq(modem_device_str, "any"))
+	if (modem_device_str && !spa_streq(modem_device_str, "any")) {
 		this->allowed_modem_device = strdup(modem_device_str);
+		if (this->allowed_modem_device == NULL)
+			return NULL;
+	}
 	spa_list_init(&this->call_list);
 	this->pts = pts;