function main() {
  $bin_repr = "\x00\x00\x00\x00\x00\x00\x00\x80";
  $double_num = unpack("dnum", $bin_repr)['num'];
  var_dump(number_format($double_num, 100));
}
The software performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.