static BROTLI_INLINE int SafeReadBlockLength(BrotliState* s,
                                             uint32_t* result,
                                             const HuffmanCode* table,
                                             BrotliBitReader* br) {
  uint32_t index;
  if (s->substate_read_block_length == BROTLI_STATE_READ_BLOCK_LENGTH_NONE) {
    if (!SafeReadSymbol(table, br, &index)) {
      return 0;
    }
  } else {
    index = s->block_length_index;
  }
  {
    uint32_t bits;
    uint32_t nbits = kBlockLengthPrefixCode[index].nbits; /* nbits == 2..24 */
    if (!BrotliSafeReadBits(br, nbits, &bits)) {
      s->block_length_index = index;
      s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_SUFFIX;
      return 0;
    }
    *result = kBlockLengthPrefixCode[index].offset + bits;
    s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_NONE;
    return 1;
  }
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.