Day Zero

nouncandidate·updated May 9, 2026

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The "Day Zero" or "Zero Day" is the day a new vulnerability is made known. In some cases, a "zero day" exploit is referred to an exploit for which no patch is available yet. ("day one"- day at which the patch is made available).

MWE

Classifications

per-axis with provenance

Entity Type

Vulnerability95%llm-generatedllm:claude-haiku-4-5

?unassignedlast reviewed —

Sensitivity

unclassified

Information Class

unclassified

Variants

3 surface forms

plural: Day Zeroes
possessive: Day Zero's
pluralpossessive: Day Zeroes'

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