Zero-Day Exploit

A zero-day exploit attacks a software or hardware vulnerability that the vendor does not yet know about or has not patched, leaving defenders zero days to prepare. Because no fix and often no signature exists, signature-based antivirus and conventional patching cannot stop it, so defense shifts to network segmentation, behavior-based detection, and least-privilege containment. For shipping the risk concentrates in long-lived OT and navigation software that is patched slowly even after a flaw becomes public. Once disclosed, a zero-day usually receives a CVE identifier and enters normal vulnerability and patch management.