static void Upsample(const size_t width,const size_t height,
  const size_t scaled_width,unsigned char *pixels)
{
  register ssize_t
    x,
    y;

  register unsigned char
    *p,
    *q,
    *r;

  /*
    Create a new image that is a integral size greater than an existing one.
  */
  assert(pixels != (unsigned char *) NULL);
  for (y=0; y < (ssize_t) height; y++)
  {
    p=pixels+(height-1-y)*scaled_width+(width-1);
    q=pixels+((height-1-y) << 1)*scaled_width+((width-1) << 1);
    *q=(*p);
    *(q+1)=(*(p));
    for (x=1; x < (ssize_t) width; x++)
    {
      p--;
      q-=2;
      *q=(*p);
      *(q+1)=(unsigned char) ((((size_t) *p)+((size_t) *(p+1))+1) >> 1);
    }
  }
  for (y=0; y < (ssize_t) (height-1); y++)
  {
    p=pixels+((size_t) y << 1)*scaled_width;
    q=p+scaled_width;
    r=q+scaled_width;
    for (x=0; x < (ssize_t) (width-1); x++)
    {
      *q=(unsigned char) ((((size_t) *p)+((size_t) *r)+1) >> 1);
      *(q+1)=(unsigned char) ((((size_t) *p)+((size_t) *(p+2))+
        ((size_t) *r)+((size_t) *(r+2))+2) >> 2);
      q+=2;
      p+=2;
      r+=2;
    }
    *q++=(unsigned char) ((((size_t) *p++)+((size_t) *r++)+1) >> 1);
    *q++=(unsigned char) ((((size_t) *p++)+((size_t) *r++)+1) >> 1);
  }
  p=pixels+(2*height-2)*scaled_width;
  q=pixels+(2*height-1)*scaled_width;
  (void) CopyMagickMemory(q,p,(size_t) (2*width));
}

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.