    void re_yy_flush_buffer (YY_BUFFER_STATE  b , yyscan_t yyscanner)
{
    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
	if ( ! b )
		return;

	b->yy_n_chars = 0;

	/* We always need two end-of-buffer characters.  The first causes
	 * a transition to the end-of-buffer state.  The second causes
	 * a jam in that state.
	 */
	b->yy_ch_buf[0] = YY_END_OF_BUFFER_CHAR;
	b->yy_ch_buf[1] = YY_END_OF_BUFFER_CHAR;

	b->yy_buf_pos = &b->yy_ch_buf[0];

	b->yy_at_bol = 1;
	b->yy_buffer_status = YY_BUFFER_NEW;

	if ( b == YY_CURRENT_BUFFER )
		re_yy_load_buffer_state(yyscanner );
}

The product dereferences a pointer that it expects to be valid but is NULL.