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.

What Is A Data Breach? Definition, Examples And Prevention

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? Definition & Prevention Guide

https://www.cyberhaven.com/infosec-essentials/what-is-data-breach
Feb 9, 2026 · In plain terms, a data breach occurs when data ends up in the wrong hands, whether through malicious intent, human error, system misconfiguration, or insider misuse. Organizations often classify incidents using specific language for regulatory and legal purposes.

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 and How to Prevent a Breach in 2026

https://www.security.org/identity-theft/breach/
Jun 11, 2026 · A data breach is a security incident in which a third party accesses data without the consent of the data’s owner, which could be either a business, its customers, or both.

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? | ICO

https://ico.org.uk/for-the-public/i-m-worried-about-how-an-organisation-has-handled-my-information/what-is-a-data-breach/
What is a data breach? Due to changes made by the Data (Use and Access) Act, this guidance is under review and may be subject to change. The Plans for new and updated guidance page will tell you about which guidance will be updated and when this will happen.

What Is a Data Breach? - Experian

https://www.experian.com/blogs/ask-experian/what-is-a-data-breach/
Apr 3, 2026 · Quick Answer A data breach is the theft of personal information, such as Social Security numbers, credit card numbers or passwords, from an organization’s digital records. Criminals may use stolen data to impersonate you and seek credit in your name.

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.