If you build a software and because of a bug it breaks something, that is fine. If you deliberately change a library to make any software running it crash and you know it is used among other things by software that control nuclear plants or elevators, my guess is it will probably considered a crime in most juridictions. This regardless of the fact said software makers should test their changes.
You're very likely right and I made a mistake. In strict legal terms anything you do can be sued if the law deems it damaging it some way or another, and the answer to this->parent's question is highly dependent on legal contexts.
I was taking a naive view from a theoretical point.
If you build a software and because of a bug it breaks something, that is fine. If you deliberately change a library to make any software running it crash and you know it is used among other things by software that control nuclear plants or elevators, my guess is it will probably considered a crime in most juridictions. This regardless of the fact said software makers should test their changes.