static Image *ReadGROUP4Image(const ImageInfo *image_info,
  ExceptionInfo *exception)
{
  char
    filename[MaxTextExtent];

  FILE
    *file;

  Image
    *image;

  ImageInfo
    *read_info;

  int
    c,
    unique_file;

  MagickBooleanType
    status;

  size_t
    length;

  ssize_t
    offset,
    strip_offset;

  /*
    Open image file.
  */
  assert(image_info != (const ImageInfo *) NULL);
  assert(image_info->signature == MagickSignature);
  if (image_info->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
      image_info->filename);
  assert(exception != (ExceptionInfo *) NULL);
  assert(exception->signature == MagickSignature);
  image=AcquireImage(image_info);
  status=OpenBlob(image_info,image,ReadBinaryBlobMode,exception);
  if (status == MagickFalse)
    {
      image=DestroyImageList(image);
      return((Image *) NULL);
    }
  /*
    Write raw CCITT Group 4 wrapped as a TIFF image file.
  */
  file=(FILE *) NULL;
  unique_file=AcquireUniqueFileResource(filename);
  if (unique_file != -1)
    file=fdopen(unique_file,"wb");
  if ((unique_file == -1) || (file == (FILE *) NULL))
    ThrowImageException(FileOpenError,"UnableToCreateTemporaryFile");
  length=fwrite("\111\111\052\000\010\000\000\000\016\000",1,10,file);
  length=fwrite("\376\000\003\000\001\000\000\000\000\000\000\000",1,12,file);
  length=fwrite("\000\001\004\000\001\000\000\000",1,8,file);
  length=WriteLSBLong(file,image->columns);
  length=fwrite("\001\001\004\000\001\000\000\000",1,8,file);
  length=WriteLSBLong(file,image->rows);
  length=fwrite("\002\001\003\000\001\000\000\000\001\000\000\000",1,12,file);
  length=fwrite("\003\001\003\000\001\000\000\000\004\000\000\000",1,12,file);
  length=fwrite("\006\001\003\000\001\000\000\000\000\000\000\000",1,12,file);
  length=fwrite("\021\001\003\000\001\000\000\000",1,8,file);
  strip_offset=10+(12*14)+4+8;
  length=WriteLSBLong(file,(size_t) strip_offset);
  length=fwrite("\022\001\003\000\001\000\000\000",1,8,file);
  length=WriteLSBLong(file,(size_t) image_info->orientation);
  length=fwrite("\025\001\003\000\001\000\000\000\001\000\000\000",1,12,file);
  length=fwrite("\026\001\004\000\001\000\000\000",1,8,file);
  length=WriteLSBLong(file,image->rows);
  length=fwrite("\027\001\004\000\001\000\000\000\000\000\000\000",1,12,file);
  offset=(ssize_t) ftell(file)-4;
  length=fwrite("\032\001\005\000\001\000\000\000",1,8,file);
  length=WriteLSBLong(file,(size_t) (strip_offset-8));
  length=fwrite("\033\001\005\000\001\000\000\000",1,8,file);
  length=WriteLSBLong(file,(size_t) (strip_offset-8));
  length=fwrite("\050\001\003\000\001\000\000\000\002\000\000\000",1,12,file);
  length=fwrite("\000\000\000\000",1,4,file);
  length=WriteLSBLong(file,(size_t) (image->x_resolution+0.5));
  length=WriteLSBLong(file,1);
  for (length=0; (c=ReadBlobByte(image)) != EOF; length++)
    (void) fputc(c,file);
  offset=(ssize_t) fseek(file,(ssize_t) offset,SEEK_SET);
  length=WriteLSBLong(file,(unsigned int) length);
  (void) fclose(file);
  (void) CloseBlob(image);
  image=DestroyImage(image);
  /*
    Read TIFF image.
  */
  read_info=CloneImageInfo((ImageInfo *) NULL);
  (void) FormatLocaleString(read_info->filename,MaxTextExtent,"%s",filename);
  image=ReadTIFFImage(read_info,exception);
  read_info=DestroyImageInfo(read_info);
  if (image != (Image *) NULL)
    {
      (void) CopyMagickString(image->filename,image_info->filename,
        MaxTextExtent);
      (void) CopyMagickString(image->magick_filename,image_info->filename,
        MaxTextExtent);
      (void) CopyMagickString(image->magick,"GROUP4",MaxTextExtent);
    }
  (void) RelinquishUniqueFileResource(filename);
  return(image);
}

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.