An event queue is a buffer that stores actions or signals until an application is ready to process them. Software commonly uses queues to pass work between components, handle incoming messages, or manage events in sequence without requiring each part of the program to act immediately.
In cyber security, queue handling matters because delayed, duplicated, or incorrectly ordered events can leave software in an unsafe or inconsistent state. In calling software, for example, hang-up and session-cleanup signals may wait in a queue before processing. If shutdown events are lost or handled too late, a call might not end as expected. Defenses include validating events, handling failures and timeouts, and testing that security-critical transitions-such as session teardown-complete reliably.