Yahoo Data Breach History

This page tracks the Yahoo data breach history and cybersecurity incidents affecting Yahoo (United States). BreachHistory currently indexes 11 publicly disclosed or catalogued incidents spanning 2010 through 2017, with approximately 6.1 billion records reported as exposed across all indexed events. These totals may include overlapping datasets or third-party estimates and should not be interpreted as unique affected users.

The Yahoo breach timeline includes major data breaches, cyber attacks, data leaks, credential exposures, API abuse, and other security incidents. Each incident provides details on the estimated records exposed, attack method, affected data types, and supporting public sources. Currently, 0 incidents are company-confirmed.

Largest Yahoo Data Breaches

The largest indexed incidents include the 2013 breach (disclosed 2016) — all accounts, the 2016 — Yahoo: Happened in 2013 but only disclosed late 2016, 1000.0M records, and the 2013 — Yahoo: Happened in 2013 but only disclosed late 2016, 1000.0M records, along with additional historical incidents involving exposed passwords, public databases, and large-scale data scraping. Record counts originating from threat actors or leak sites should be treated as estimates unless confirmed by Yahoo or a regulator. Below is the list of large data breaches:

• 2013 2013 breach (disclosed 2016) — all accounts — about 3.0B records exposed · Catalogued incident
• 2016 2016 — Yahoo: Happened in 2013 but only disclosed late 2016, 1000.0M records — about 1.0B records exposed · Catalogued incident
• 2013 2013 — Yahoo: Happened in 2013 but only disclosed late 2016, 1000.0M records — about 1.0B records exposed · Catalogued incident
• 2016 2016 — Yahoo: Happened in 2014, but no, 500.0M records — about 500.0M records exposed · Catalogued incident
• 2014 2014 breach (disclosed 2016) — 500M accounts — about 500.0M records exposed · Catalogued incident
• 2017 2017 — Yahoo: User accounts have been hacked using forged cookies… — about 32.0M records exposed · Catalogued incident
• 2010 2010 — Yahoo: User accounts have been hacked using forged cookies… — about 32.0M records exposed · Catalogued incident
• 2013 2013 — Yahoo Japan: Hacking, 22,000,000 records — about 22.0M records exposed · Catalogued incident

What Information Was Exposed?

Depending on the incident, exposed data may include email addresses, passwords and login credentials, phone numbers, names, physical addresses, health and medical (PHI) records, and other personal information (PII). The exact data varies between incidents, so review each breach page before assuming your information was affected.

Yahoo Data Breach 2026

At the time of this update, no Yahoo data breach has been catalogued for 2026. New incidents are added as official disclosures, regulatory filings, or credible cybersecurity reports become available.

What To Do If You Were Affected

If you believe your account may have been involved in a Yahoo data breach, change any reused passwords, enable multi-factor authentication (MFA), monitor your account for suspicious activity, and be cautious of phishing emails or fake breach notifications.

This Yahoo breach history is maintained by BreachHistory using public disclosures, regulatory filings, security research, and clearly labelled third-party claims. For the complete breach timeline, records exposed, incident details, and AI Breach Risk Score, explore the sections on this page.