What is a data breach? - IBM

https://www.ibm.com/think/topics/data-breach
A data breach is any security incident in which unauthorized parties access sensitive or confidential information, including personal data (Social Security numbers, bank account numbers, healthcare data) and corporate data (customer records, intellectual property, financial information).

What Is a Data Breach? | Microsoft Security

https://www.microsoft.com/en-us/security/business/security-101/what-is-a-data-breach
May 29, 2026 · A data breach is a security incident in which protected, confidential, or sensitive data is accessed, acquired, or disclosed without authorization, or is misused by authorized users beyond their intended permissions.

Data breach - Wikipedia

https://en.m.wikipedia.org/wiki/Data_breach
Data breach A data breach, also known as data leakage, is "the unauthorized exposure, disclosure, or loss of personal information ". [1] Attackers have a variety of motives, from financial gain to political activism, political repression, and espionage.

What Is A Data Breach? Definition, Examples & Prevention - Forbes

https://www.forbes.com/advisor/business/what-is-data-breach/
Apr 10, 2026 · A data breach is a security incident in which bad actors gain access to one or more computer systems and expose data—or demand payment to return the data (a ransomware attack).

What is a data breach? - Cisco

https://www.cisco.com/site/us/en/learn/topics/security/what-is-a-data-breach.html
A data breach is a security violation or incident that leads to the theft of sensitive or critical data or its exposure to an unauthorized party. These incidents can be intentional, such as a database hack, or accidental, such as an employee emailing confidential files to the wrong recipient.

What is a Data Breach and How to Prevent a Breach in 2026

https://www.security.org/identity-theft/breach/
Jun 11, 2026 · Data breaches expose millions; Equifax's 2017 breach leaked info of 147.9M Americans. Protect with strong passwords, software updates, and credit monitoring. Data breach – we hear and read about it in the news and data experts warn us about it – but what really is a data breach? And more importantly, how does it affect us, personally?

What is a Data Breach? Definition & Prevention Guide

https://www.cyberhaven.com/infosec-essentials/what-is-data-breach
Feb 9, 2026 · A data breach is a security incident in which sensitive, confidential, or protected information is accessed, disclosed, stolen, or used without authorization. Data breaches can involve personal data, financial records, intellectual property, customer information, or regulated data such as healthcare or payment card information. In plain terms, a data breach occurs when data ends up in the ...

What Is a Data Breach? - Experian

https://www.experian.com/blogs/ask-experian/what-is-a-data-breach/
Apr 3, 2026 · Learn what data breaches are, how they happen and what to do if your data is exposed. Plus, find out what it means if you get a breach notification.

What is a Data Breach? Definition & Examples | Sans Institute

https://www.sans.org/security-resources/glossary-of-terms/data-breach
What is a data breach? Learn the definition, common causes, and real-world examples of data breaches, plus how to protect your business, here.