Explain the concept of zero-day vulnerability.

Explain the concept of zero-day vulnerability.

A zero-day vulnerability refers to a security flaw or weakness in a software or system that is unknown to the vendor or developer. It is called "zero-day" because it is exploited by hackers or attackers before the software or system's creator has had zero days to fix or patch the vulnerability. This means that there is no prior knowledge or defense against the vulnerability, making it highly dangerous and difficult to detect or prevent. Zero-day vulnerabilities are often exploited to launch targeted attacks, steal sensitive information, or gain unauthorized access to systems.