The classification criteria should ensure that all relevant types of major incidents are captured. Cyber attacks related to intrusion into network or information systems may not necessarily be captured by many classification criteria. However, they are important since any intrusion in network and information systemsmeans a network and information system as defined in Article 6, point 1, of Directive (EU) 2022/2555; may harm the financial entity. Accordingly, the classification criteria ‘critical services affected’ and ‘data losses’ should be specified in such a way as to capture these types of major incidents, in particular unauthorised intrusions which, even if the impacts are not immediately known, may lead to serious consequences, in particular data breaches and data leakages.