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Zero-day

UK //ˈzɪərəʊ deɪ// US //ˈziːroʊ deɪ// Pronunciation

Definition

A newly discovered vulnerability in software that is exploited before the vendor releases a fix.

Listen to definition

In simple words: A new software vulnerability that is not yet fixed.

Examples

• The hackers utilized a zero-day to breach the company's security systems.
• Experts are warning about a zero-day discovered in popular web browsers.
• Proactive measures can help defend against zero-day attacks.
• Many organizations invest heavily in zero-day protection solutions.
• The revelation of a zero-day in a widely used application creates panic among users.

Usage notes

Used mainly in cybersecurity contexts. Not suitable for casual conversation; more relevant in tech discussions.

Grammar pattern

standalone term

Memory hint

Think of 'zero' as the start, meaning it hasn't been discovered or fixed yet.

Collocations

• zero-day vulnerability
• zero-day exploit
• zero-day attack
• zero-day threat
• zero-day patch

Synonyms

• exploit
• vulnerability
• security flaw
• threat
• attack

Common mistakes

• Confusing zero-day with regular software updates.
• Using zero-day to refer to minor bugs instead of major vulnerabilities.
• Misunderstanding zero-day as an outdated term.