long ContentEncoding::ParseCompressionEntry(long long start, long long size,
 IMkvReader* pReader,
 ContentCompression* compression) {
  assert(pReader);
  assert(compression);

 long long pos = start;
 const long long stop = start + size;

 bool valid = false;

 while (pos < stop) {
 long long id, size;
 const long status = ParseElementHeader(pReader, pos, stop, id, size);
 if (status < 0) // error
 return status;

 if (id == 0x254) {
 long long algo = UnserializeUInt(pReader, pos, size);
 if (algo < 0)
 return E_FILE_FORMAT_INVALID;
      compression->algo = algo;
      valid = true;
 } else if (id == 0x255) {
 if (size <= 0)
 return E_FILE_FORMAT_INVALID;

 const size_t buflen = static_cast<size_t>(size);
 unsigned char* buf = SafeArrayAlloc<unsigned char>(1, buflen);
 if (buf == NULL)
 return -1;

 const int read_status =
          pReader->Read(pos, static_cast<long>(buflen), buf);
 if (read_status) {
 delete[] buf;
 return status;
 }

      compression->settings = buf;
      compression->settings_len = buflen;
 }

    pos += size; // consume payload
 if (pos > stop)
 return E_FILE_FORMAT_INVALID;
 }

 if (!valid)
 return E_FILE_FORMAT_INVALID;

 return 0;
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.