Collection No. 1 Data Breach History
WebsiteCollection No. 1 was a large compilation of breached credentials.
This page shows all data breaches of Collection No. 1. View the complete breach timeline, records exposed, root causes, and AI breach risk score. BreachHistory tracks disclosed data breaches worldwide.
Data Breach Timeline — All Collection No. 1 Breaches
Collection No. 1 Data Breach Summary
This page tracks the Collection No. 1 data breach history and cybersecurity incidents affecting Collection No. 1 (Unknown). BreachHistory currently indexes 1 publicly disclosed or catalogued incident spanning 2019, with approximately 773.0 million 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 Collection No. 1 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 Collection No. 1 Data Breaches
The largest indexed incidents include the 2019 — Collection No. 1: compilation of multiple data breaches, 773,000,000 records. Record counts originating from threat actors or leak sites should be treated as estimates unless confirmed by Collection No. 1 or a regulator. Below is the list of large data breaches:
- 2019 2019 — Collection No. 1: compilation of multiple data breaches, 773,000,000 records — about 773.0M records exposed · Catalogued incident
What Information Was Exposed?
Depending on the incident, exposed data may include 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.
Collection No. 1 Data Breach 2026
At the time of this update, no Collection No. 1 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 Collection No. 1 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 Collection No. 1 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.