Anthropic Tells Korea Regulator 100 Corporate Claude Accounts Leaked

Anthropic reported on Oct. 31 that data from about 100 South Korean corporate Claude accounts leaked, the Personal Information Protection Commission says, and the regulator is reviewing the case before a formal investigation. Anthropic researcher Lydia Harley said on X that intruders reached account names, emails and subscription plans but not prompts, AI outputs or payment data.

• The Washington Post reports Cathedral, a U.S. security startup, reaches Anthropic's internal systems through a vulnerability in third-party business software.
• The Personal Information Protection Commission says it plans to confirm the specific scale of damage through further inquiry once a formal investigation begins.
• Anthropic tells corporate customers account and organization identification numbers and business contact details including names and emails may have been exposed.