What is a zero-day vulnerability?

A zero-day vulnerability refers to a security flaw in software that is exploited by attackers before the vendor has a chance to release a fix or patch. This means that the time between the discovery of the vulnerability and the deployment of a fix is zero days, as the vendor is unaware of the issue at the time it is being exploited.

The significance of zero-day vulnerabilities lies in their potential impact; since there is no existing defense against them yet, they can be particularly dangerous. Attackers can exploit these vulnerabilities to gain unauthorized access, steal data, or compromise systems without detection. Because the vendor is still unaware of the flaw, users remain vulnerable until a solution is developed and distributed.

Understanding zero-day vulnerabilities is crucial for cybersecurity professionals, as they must remain vigilant and proactive in protecting systems against such threats that have yet to be mitigated.