---- cli.c:cli_out ----

        va_start (ap, fmt);

#ifdef HAVE_READLINE
        if (state->rl_enabled && !state->rl_processing)
                return cli_rl_out(state, fmt, ap);
#endif

        ret = vprintf (fmt, ap);
        printf ("\n");

---- cli.c:cli_out ----

Man page says: Each  invocation  of  va_start()  must  be  matched  by  a corresponding invocation of va_end() in the same function.