Chess.com (2026) data breach
In August 2026, millions of records allegedly sourced from Chess.com were posted online. The data contained 7.3M rows with 4.6M unique email addresses, along with usernames, names, countries and data relating to users' Chess.com accounts. Analysis of the data suggested it had been obtained by scraping. When loaded into HIBP, 99% of the email addresses had already appeared in previous data breaches, further supporting the scraping theory. Read more about scrapes and data breaches.
Sources
- Primary: https://www.chess.com/forum/view/general/chess-com-hacked-again
- Upstream record (Have I Been Pwned): https://haveibeenpwned.com/Breach/Chess2026
- Breach data from Have I Been Pwned (haveibeenpwned.com), CC BY 4.0
Defenses for this class of incident
all categoriesA data breach sits in these classes of the AI-security landscape. The companies below work on that class of problem. This is a taxonomy, not a claim that any of them would have changed this incident.
Vendor data: AI Security Startups Map by Prompt Security (CC BY 4.0), synced daily. startups.prompt.security. Paid placements are labelled Sponsored; HeimWall, which runs this site, is labelled Operator. 453 companies in the directory.
Wrong or missing? Email founders@heimwall.ai. Corrections are logged here, in place. How corrections and takedowns work.