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Software Engineering vocabulary · APIs, Networking and Security

Zero-day

Meaning in software engineering, with examples

nounCore term

In software engineering, zero-day means: A vulnerability that is unknown to the vendor or has no patch yet, so defenders have had 'zero days' to fix it when it is first exploited.

In Turkish: sıfırıncı gün açığı, zero-day

How it is used

Used as a noun ('a zero-day') and as an adjective ('a zero-day vulnerability', 'a zero-day exploit'). Zero-days are rare and valuable, so they make the news, but most real attacks still use known, unpatched vulnerabilities. Also written 0-day.

Example sentences

  1. The attackers used a zero-day in the mail server, so there was no patch to apply.

  2. The vendor confirmed the zero-day and published a temporary workaround.

Common collocations

  • zero-day vulnerability
  • zero-day exploit
  • exploited zero-day
  • zero-day attack
  • vulnerabilityA weakness in software, hardware, a configuration or a process that an attacker could use to cause harm or to gain access they should not have.
  • exploitA piece of code or a technique that takes advantage of a vulnerability to make a system do something it was not designed to do.
  • patchA small update that fixes bugs or security problems in software without adding big new features. It is also a verb: to patch a system.
  • responsible disclosureReporting a vulnerability privately to the vendor or owner first and giving them reasonable time to fix it before any details are made public.

This word in other fields

The same English word can have a different meaning in another field:

More terms: APIs, Networking and Security

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