Yep, I heard of machines in Texas and two other states switching a choice from Trump to Hillary - they were probably badly coded in the first place. Jill Stein, Green Party candidate, warned of other weaknesses. It is a flaw of election system as it is and can be fixed before the next election.
I could probably mention counting votes can be done via network without connecting to the WWW, but would likely be expensive. North Korea has a great security against cyber threats, because it has very few computers connected to World Wide Web :)