png_process_some_data(png_structp png_ptr, png_infop info_ptr)
{
   if (png_ptr == NULL)
      return;

   switch (png_ptr->process_mode)
   {
      case PNG_READ_SIG_MODE:
      {
         png_push_read_sig(png_ptr, info_ptr);
         break;
      }

      case PNG_READ_CHUNK_MODE:
      {
         png_push_read_chunk(png_ptr, info_ptr);
         break;
      }

      case PNG_READ_IDAT_MODE:
      {
         png_push_read_IDAT(png_ptr);
         break;
      }

      case PNG_SKIP_MODE:
      {
         png_push_crc_finish(png_ptr);
         break;
      }

      default:
      {
         png_ptr->buffer_size = 0;
         break;
      }
   }
}

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.