diff --git a/client/main.c b/client/main.c
index feb21a1..6b938da 100644
--- a/client/main.c
+++ b/client/main.c
@@ -843,6 +843,18 @@ static gboolean parse_argument(int argc, char *argv[], const char **arg_table,
 	return FALSE;
 }
 
+static int validate_input(int argc, char *argv[])
+{
+	for (int i = 0; i < argc; i++) {
+		if (!strisutf8(argv[i], strlen(argv[i]))) {
+			printf("Invalid character in string: %s\n", argv[i]);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 static void cmd_list(int argc, char *argv[])
 {
 	GList *list;
@@ -3299,6 +3311,10 @@ int main(int argc, char *argv[])
 	int timeout;
 	unsigned int timeout_id;
 
+	status = validate_input(argc, argv);
+	if (status)
+		return status;
+
 	bt_shell_init(argc, argv, &opt);
 	bt_shell_set_menu(&main_menu);
 	bt_shell_add_submenu(&advertise_menu);