Steam Data Breach History

This page tracks the Steam data breach history and cybersecurity incidents affecting Steam (United States). BreachHistory currently indexes 2 publicly disclosed or catalogued incidents spanning 2011, with approximately 70.0 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 Steam 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 Steam Data Breaches

The largest indexed incidents include the 2011 — Steam: The November 6 defacement of Steam forums led to an… and the 2011 — Steam: The Valve Corporation, 35.0M records. Record counts originating from threat actors or leak sites should be treated as estimates unless confirmed by Steam or a regulator. Below is the list of large data breaches:

• 2011 2011 — Steam: The November 6 defacement of Steam forums led to an… — about 35.0M records exposed · Catalogued incident
• 2011 2011 — Steam: The Valve Corporation, 35.0M records — about 35.0M records exposed · Catalogued incident

What Information Was Exposed?

Depending on the incident, exposed data may include email addresses, passwords, phone numbers, names, profile information, account identifiers, and other personal information (PII). The exact data varies between incidents, so review each breach page before assuming your information was affected.

Steam Data Breach 2026

At the time of this update, no Steam 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 Steam 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 Steam 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.