MagickExport RectangleInfo GetImageBoundingBox(const Image *image,
  ExceptionInfo *exception)
{
  CacheView
    *image_view;

  MagickBooleanType
    status;

  MagickPixelPacket
    target[3],
    zero;

  RectangleInfo
    bounds;

  register const PixelPacket
    *p;

  ssize_t
    y;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  bounds.width=0;
  bounds.height=0;
  bounds.x=(ssize_t) image->columns;
  bounds.y=(ssize_t) image->rows;
  GetMagickPixelPacket(image,&target[0]);
  image_view=AcquireVirtualCacheView(image,exception);
  p=GetCacheViewVirtualPixels(image_view,0,0,1,1,exception);
  if (p == (const PixelPacket *) NULL)
    {
      image_view=DestroyCacheView(image_view);
      return(bounds);
    }
  SetMagickPixelPacket(image,p,GetCacheViewVirtualIndexQueue(image_view),
    &target[0]);
  GetMagickPixelPacket(image,&target[1]);
  p=GetCacheViewVirtualPixels(image_view,(ssize_t) image->columns-1,0,1,1,
    exception);
  if (p != (const PixelPacket *) NULL)
    SetMagickPixelPacket(image,p,GetCacheViewVirtualIndexQueue(image_view),
      &target[1]);
  GetMagickPixelPacket(image,&target[2]);
  p=GetCacheViewVirtualPixels(image_view,0,(ssize_t) image->rows-1,1,1,
    exception);
  if (p != (const PixelPacket *) NULL)
    SetMagickPixelPacket(image,p,GetCacheViewVirtualIndexQueue(image_view),
      &target[2]);
  status=MagickTrue;
  GetMagickPixelPacket(image,&zero);
#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++)
  {
    MagickPixelPacket
      pixel;

    RectangleInfo
      bounding_box;

    register const IndexPacket
      *magick_restrict indexes;

    register const PixelPacket
      *magick_restrict p;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#   pragma omp critical (MagickCore_GetImageBoundingBox)
#endif
    bounding_box=bounds;
    p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
    if (p == (const PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewVirtualIndexQueue(image_view);
    pixel=zero;
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      SetMagickPixelPacket(image,p,indexes+x,&pixel);
      if ((x < bounding_box.x) &&
          (IsMagickColorSimilar(&pixel,&target[0]) == MagickFalse))
        bounding_box.x=x;
      if ((x > (ssize_t) bounding_box.width) &&
          (IsMagickColorSimilar(&pixel,&target[1]) == MagickFalse))
        bounding_box.width=(size_t) x;
      if ((y < bounding_box.y) &&
          (IsMagickColorSimilar(&pixel,&target[0]) == MagickFalse))
        bounding_box.y=y;
      if ((y > (ssize_t) bounding_box.height) &&
          (IsMagickColorSimilar(&pixel,&target[2]) == MagickFalse))
        bounding_box.height=(size_t) y;
      p++;
    }
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#   pragma omp critical (MagickCore_GetImageBoundingBox)
#endif
    {
      if (bounding_box.x < bounds.x)
        bounds.x=bounding_box.x;
      if (bounding_box.y < bounds.y)
        bounds.y=bounding_box.y;
      if (bounding_box.width > bounds.width)
        bounds.width=bounding_box.width;
      if (bounding_box.height > bounds.height)
        bounds.height=bounding_box.height;
    }
  }
  image_view=DestroyCacheView(image_view);
  if ((bounds.width == 0) && (bounds.height == 0))
    (void) ThrowMagickException(exception,GetMagickModule(),OptionWarning,
      "GeometryDoesNotContainImage","`%s'",image->filename);
  else
    {
      bounds.width-=(bounds.x-1);
      bounds.height-=(bounds.y-1);
    }
  return(bounds);
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.