Zero-day attacks

1. A cyber exploit that relies on exploiting an unknown or undisclosed vulnerability in the design or implementation of a system to violate its security.

Source: U.S. Cyberspace Solarium Commission, March 2020, https://subscriber.politicopro.com/f/?id=00000170-c638-d8f7-a7f1-f63b33510000

2. A threat that takes advantage of a previously unknown system or network vulnerability that developers haven’t yet had time to patch.

Source: Guide to Cybersecurity as Risk Management: The Role of Elected Officials, Governing Institute, CGI, https://www.cgi.com/sites/default/files/2019-03/guide_to_cybersecurity_as_risk_management_the_role_of_elected_officials_0.pdf