As his point of departure Prof David Wallace takes the uniqueness of the environment in which cyber weapons are conceived, developed and ultimately applied and the legal implications thereof. In the light of this, the regular weapons review procedure as foreseen in Article 36 of 1977 Additional Protocol I to the Geneva Conventions faces multiple challenges, that range from the definition of „cyber weapon“ to technical issues of targeting, distinction and foreseeability. Also, the paper examines the legally and technologically thin line between cyber weapons development and espionage. The author argues that all of the foregoing when combined with the traditionally state-centric nature of Article 36 weapons review make international regulation and efficient oversight highly complicated yet urgently needed.