Eastern Bank notified Massachusetts customers on May 13, 2026, that a merchant accepting Eastern Bank Debit MasterCard BusinessCards experienced a security breach. The bank could not obtain details from the merchant. Eastern Bank took proactive measures including lowering card limits to $500 and issuing new debit cards to affected customers. Customers were instructed to activate new cards, destroy old ones, and monitor accounts for suspicious activity. No specific data types or counts were disclosed.