A security approach that gives users access only to the specific systems or applications they need. Rather than trusting someone just because they are on the network, ZTNA checks identity, device security, and context before allowing access.

An attack that targets a previously unknown vulnerability in software or hardware before a fix is available. Because there’s no existing defense, zero-day exploits are highly dangerous and often used in advanced cyber attacks.

A security flaw in software or hardware that is exploited by attackers before the vendor has released a fix.