copy_cairo_surface_to_pixbuf (cairo_surface_t *surface,
			      unsigned char   *data,
			      GdkPixbuf       *pixbuf)
{
  int cairo_width, cairo_height, cairo_rowstride;
  unsigned char *pixbuf_data, *dst, *cairo_data;
  int pixbuf_rowstride, pixbuf_n_channels;
  unsigned int *src;
  int x, y;

  cairo_width = cairo_image_surface_get_width (surface);
  cairo_height = cairo_image_surface_get_height (surface);
  cairo_rowstride = cairo_width * 4;
  cairo_data = data;

  pixbuf_data = gdk_pixbuf_get_pixels (pixbuf);
  pixbuf_rowstride = gdk_pixbuf_get_rowstride (pixbuf);
  pixbuf_n_channels = gdk_pixbuf_get_n_channels (pixbuf);

  if (cairo_width > gdk_pixbuf_get_width (pixbuf))
    cairo_width = gdk_pixbuf_get_width (pixbuf);
  if (cairo_height > gdk_pixbuf_get_height (pixbuf))
    cairo_height = gdk_pixbuf_get_height (pixbuf);
  for (y = 0; y < cairo_height; y++)
    {
      src = (unsigned int *) (cairo_data + y * cairo_rowstride);
      dst = pixbuf_data + y * pixbuf_rowstride;
      for (x = 0; x < cairo_width; x++) 
	{
	  dst[0] = (*src >> 16) & 0xff;
	  dst[1] = (*src >> 8) & 0xff; 
	  dst[2] = (*src >> 0) & 0xff;
	  if (pixbuf_n_channels == 4)
	      dst[3] = (*src >> 24) & 0xff;
	  dst += pixbuf_n_channels;
	  src++;
	}
    }
}	

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.