While the plea of necessity may be available for states in their responses to cyberattacks, frequent and pretextual invocations of necessity may destabilize international peace and security. Tallinn Manual 2.0 recognizes the plea of necessity, drawing on classic examples of necessity from traditional international customary law sources, but the application of these sources to cyberwarfare presents unique concerns. Although pleas of necessity require states to identify their essential interests, allowing states to unilaterally define these interests or limit the concept of critical infrastructure raises questions for the applicability of the necessity doctrine. Additionally, the cyber operations have uncertain and unpredictable effects, thus making it difficult to determine when the last “window of opportunity” for responsive action is about to close. States seeking to clarify vague definitions and better understand legitimate responsive action first ought to commit to procedural norms to establish accountability so that a better international consensus on the plea of necessity may emerge.