Nuclear weapons and related systems are increasingly vulnerable to sophisticated cyberattacks, and nuclear-armed states must cooperate and accelerate efforts to prevent an attack that could have catastrophic consequences, according to a new report from the Nuclear Threat Initiative (NTI), Nuclear Weapons in the New CyberAge: A Report of the Cyber-Nuclear Weapons Study Group. The report finds that cyber threats to nuclear weapons and related systems—including nuclear planning systems, early warning systems, communication systems, and delivery systems—increase the risk of unauthorized use of a nuclear weapon, increase the risk of nuclear use as a result of false warnings, and could undermine confidence in the nuclear deterrent. This is because the speed, stealth, unpredictability, and challenges of attribution of any particular cyberattack make it increasingly difficult to anticipate, deter, and defend against all cyber threats.