static MagickBooleanType ApplyPSDOpacityMask(Image *image,const Image *mask,
  Quantum background,MagickBooleanType revert,ExceptionInfo *exception)
{
  Image
    *complete_mask;

  MagickBooleanType
    status;

  PixelInfo
    color;

  ssize_t
    y;

  if (image->debug != MagickFalse)
    (void) LogMagickEvent(CoderEvent,GetMagickModule(),
      "  applying opacity mask");
  complete_mask=CloneImage(image,image->columns,image->rows,MagickTrue,
    exception);
  complete_mask->alpha_trait=BlendPixelTrait;
  GetPixelInfo(complete_mask,&color);
  color.red=background;
  SetImageColor(complete_mask,&color,exception);
  status=CompositeImage(complete_mask,mask,OverCompositeOp,MagickTrue,
    mask->page.x-image->page.x,mask->page.y-image->page.y,exception);
  if (status == MagickFalse)
    {
      complete_mask=DestroyImage(complete_mask);
      return(status);
    }
  image->alpha_trait=BlendPixelTrait;
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(static,4) shared(status) \
  magick_threads(image,image,image->rows,1)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register Quantum
      *magick_restrict q;

    register Quantum
      *p;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetAuthenticPixels(image,0,y,image->columns,1,exception);
    p=GetAuthenticPixels(complete_mask,0,y,complete_mask->columns,1,exception);
    if ((q == (Quantum *) NULL) || (p == (Quantum *) NULL))
      {
        status=MagickFalse;
        continue;
      }
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      MagickRealType
        alpha,
        intensity;

      alpha=GetPixelAlpha(image,q);
      intensity=GetPixelIntensity(complete_mask,p);
      if (revert == MagickFalse)
        SetPixelAlpha(image,ClampToQuantum(intensity*(QuantumScale*alpha)),q);
      else if (intensity > 0)
        SetPixelAlpha(image,ClampToQuantum((alpha/intensity)*QuantumRange),q);
      q+=GetPixelChannels(image);
      p+=GetPixelChannels(complete_mask);
    }
    if (SyncAuthenticPixels(image,exception) == MagickFalse)
      status=MagickFalse;
  }
  complete_mask=DestroyImage(complete_mask);
  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.