static MagickStatusType ReadPSDChannelZip(Image *image,const size_t channels,
  const ssize_t type,const PSDCompressionType compression,
  const size_t compact_size,ExceptionInfo *exception)
{
  MagickStatusType
    status;

  register unsigned char
    *p;

  size_t
    count,
    length,
    packet_size,
    row_size;

  ssize_t
    y;

  unsigned char
    *compact_pixels,
    *pixels;

  z_stream
    stream;

  if (image->debug != MagickFalse)
    (void) LogMagickEvent(CoderEvent,GetMagickModule(),
       "      layer data is ZIP compressed");

  compact_pixels=(unsigned char *) AcquireQuantumMemory(compact_size,
    sizeof(*compact_pixels));
  if (compact_pixels == (unsigned char *) NULL)
    ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
      image->filename);

  packet_size=GetPSDPacketSize(image);
  row_size=image->columns*packet_size;
  count=image->rows*row_size;

  pixels=(unsigned char *) AcquireQuantumMemory(count,sizeof(*pixels));
  if (pixels == (unsigned char *) NULL)
    {
      compact_pixels=(unsigned char *) RelinquishMagickMemory(compact_pixels);
      ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
        image->filename);
    }

  ResetMagickMemory(&stream, 0, sizeof(z_stream));
  stream.data_type=Z_BINARY;
  (void) ReadBlob(image,compact_size,compact_pixels);

  stream.next_in=(Bytef *)compact_pixels;
  stream.avail_in=(unsigned int) compact_size;
  stream.next_out=(Bytef *)pixels;
  stream.avail_out=(unsigned int) count;

  if(inflateInit(&stream) == Z_OK)
    {
      int
        ret;

      while (stream.avail_out > 0)
      {
        ret=inflate(&stream, Z_SYNC_FLUSH);
        if (ret != Z_OK && ret != Z_STREAM_END)
        {
          compact_pixels=(unsigned char *) RelinquishMagickMemory(
            compact_pixels);
          pixels=(unsigned char *) RelinquishMagickMemory(pixels);
          return(MagickFalse);
        }
      }
    }

  if (compression == ZipWithPrediction)
  {
     p=pixels;
     while(count > 0)
     {
       length=image->columns;
       while(--length)
       {
         if (packet_size == 2)
           {
             p[2]+=p[0]+((p[1]+p[3]) >> 8);
             p[3]+=p[1];
           }
         else
          *(p+1)+=*p;
         p+=packet_size;
       }
       p+=packet_size;
       count-=row_size;
     }
  }

  status=MagickTrue;
  p=pixels;
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    status=ReadPSDChannelPixels(image,channels,y,type,p,exception);
    if (status == MagickFalse)
      break;

    p+=row_size;
  }

  compact_pixels=(unsigned char *) RelinquishMagickMemory(compact_pixels);
  pixels=(unsigned char *) RelinquishMagickMemory(pixels);
  return(status);
}

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.