Admissibility is the legal test for whether evidence can be used in court. In cyber security, that can apply to logs, malware samples, packet captures, camera records, cloud audit trails, and other digital evidence. A file may be technically useful to investigators but still rejected if it was collected unlawfully, handled poorly, or cannot be shown to be authentic and reliable.
For defenders and investigators, admissibility depends on how data was gathered, preserved, and documented. Strong chain of custody, time stamps, hashes, access logs, and clear retention policies help prove that evidence was not altered and still reflects the original event. Attackers may try to dispute admissibility by claiming tampering, overcollection, or policy violations. That makes admissibility a practical issue in digital forensics: the value of evidence is not just what it reveals, but whether a court will trust it.