zero-day

adjective

ze·ro-day ˈzir-(ˌ)ō-ˈdā

ˈzē-(ˌ)rō-

computing

: of, relating to, or being a vulnerability (as in a computer or computer system) that is discovered and exploited (as by cybercriminals) before it is known to or addressed by the maker or vendor

Thus, in the parlance of the trade, these vulnerabilities are known as "zero-day exploits," because it has been zero days since they have been uncovered and fixed.—

James Bamford

There's a zero-day vulnerability in RealPlayer and Internet Explorer that allows malicious code to be installed …—

Mark Hopkins

… most of what's on the black market doesn't have that zero-day freshness. Criminals typically target older vulnerabilities, for which fixes have already been released …—

Lev Grossman

Examples of zero-day in a Sentence

Recent Examples on the Web Microsoft suggests the culprits may have paid for details about the zero-day exploit from other hackers, citing one such sale of an ESXi exploit that went for $1.5 million. —

Michael Kan, PCMAG, 30 July 2024 In the past 17 months, threat actors backed by the North Korean government have targeted developers twice, one of those using a zero-day vulnerability. —

Dan Goodin, Ars Technica, 15 July 2024 On the plus side, Google noticed financially motivated cybercriminals exploiting only 10 zero-day vulnerabilities, a drop from 2022. —

Michael Kan, PCMAG, 27 Mar. 2024 Out of these 97 zero-day vulnerabilities, 29 were originally discovered by Google’s security researchers. —

Davey Winder, Forbes, 27 Mar. 2024 See all Example Sentences for zero-day

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'zero-day.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.