The number of cyber incidents perpetrated by state and state-controlled actors is increasing worldwide – particularly in the OSCE area – while diplomatic instruments for mitigating them receive little attention. The OSCE (Organisation for Security and Cooperation in Europe) and other regional organizations have adopted a number of confidence-building measures (CBMs) in the cyber domain, which form the basis for deeper multilateral cooperation. However, it is unclear to what extent these measures address the requirements of a changing threat landscape. Furthermore, structural deficits in cyber diplomacy and differing threat perceptions in the respective regions persist. The fundamental question arises as to in what constellations states cooperate in the context of cyber incidents and when national sovereignty interests take precedence.