  FT_Stream_OpenMemory( FT_Stream       stream,
                        const FT_Byte*  base,
                        FT_ULong        size )
  {
    stream->base   = (FT_Byte*) base;
    stream->size   = size;
    stream->pos    = 0;
    stream->cursor = 0;
    stream->read   = 0;
    stream->close  = 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.