double GfxState::transformWidth(double w) {
  double x, y;

  x = ctm[0] + ctm[2];
  y = ctm[1] + ctm[3];
  return w * sqrt(0.5 * (x * x + y * y));
}

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