What human rights were violated during the Vietnam war?

Answer:

Yes, there were many massacres and atrocities, including the infamous My Lai Massacre in which 504 unarmed civilians were massacred by the US Army. There were also massive numbers of rapes, tortures, and killings of civilians on all sides. Arguably, the use of Agent Orange can be called a human rights violation as it's impacted generations to come with birth defects.

Both North Vietnam and the USA/South Vietnam employed widespread terror against civilians. The North Vietnamese assassinated an estimated 36,725 civilians between 1957 and 1972 and would go on to kill perhaps hundreds of thousands more after the war. Throught the war, US armed and trained South Vietnamese military and paramilitary forces engaged in killings, reprisals, and bombardments against villagers supporting the VC, killing 400,000 to 500,000 civilians between 1965 and 1975 (citing Barbra Harff). The toll is even more if you consider the US-backed Diem Regime (1955-1963; 50,000 killed) which used the same terror tactics.

There was also the CIA's infamous Phoenix Program (1968-1972), which was a coordinated effort to neutralize the civilian infrastructure of the VC through means of blackmail, kidnapping, torture, and assassination, US troops and CIA trained 'counter terror' teams did the killing. As of mid-1971 the South Vietnamese estimated the death toll due to the CIA's Phoenix Program to be approximately 40,994. During Phoenix, suspected VC were kept in tiger cages without food or water for days on end and often tortured physically. It was common to US soldiers to interrogate prisoners in planes or helicopters and subsequently throw them out (death flights).