Which best defines a cybersecurity incident?

A cybersecurity incident is best defined as an event that compromises system confidentiality, integrity, or availability. This definition aligns with the core objectives of cybersecurity, which are to protect data and ensure that systems remain secure and functional. An incident typically involves unauthorized access, data breaches, system vulnerabilities, or attacks that could result in data theft, loss, or disruption of service.

The integrity of a system refers to the protection against unauthorized modification, while confidentiality focuses on safeguarding sensitive information from unauthorized access. Availability ensures that systems are operational and accessible when needed. Therefore, if any of these three aspects are compromised, it constitutes a valid cybersecurity incident.

Understanding this concept is critical because it emphasizes the importance of vigilance in maintaining the security posture of systems and reinforces the need for response protocols when an incident occurs. The other options surrounding system upgrades, user interaction, and system integrity do not pertain to security breaches or threats and therefore do not meet the criteria for a cybersecurity incident.