GF_Err dimm_Write(GF_Box *s, GF_BitStream *bs)
{
	GF_Err e;
	GF_DIMMBox *ptr = (GF_DIMMBox *)s;
	if (ptr == NULL) return GF_BAD_PARAM;
	e = gf_isom_box_write_header(s, bs);
	if (e) return e;
	gf_bs_write_u64(bs, ptr->nbBytes);
	return GF_OK;
}

The product reads data past the end, or before the beginning, of the intended buffer.