A zero-day vulnerability is a security flaw unknown to the vendor or for which no patch exists. The term zero-day means developers have had zero days to address the issue. Zero-days are extremely dangerous because there are no available defenses. They are traded on black markets and by government agencies. Organizations defend against zero-days through defense in depth, behavior-based detection, network segmentation, and incident response planning. Responsible disclosure helps vendors create patches before widespread exploitation.
Cybersecurity