SMBC Reports Leak of 227,216 Email Addresses After Third-Party Service Breach

• Sumitomo Mitsui Banking disclosed on November 5, 2026, that unauthorized access to Arara’s email distribution service exposed 227,216 email addresses.
• The leak covered recipients of SMBC emails sent between July 1 and October 31, 2026, primarily corporate customers.
• Arara initially reported no evidence of leakage on October 28; further investigation confirmed the exposure on November 2.
• The exposed information excluded bank account details and login credentials, but affected customers could face impersonation emails.
• SMBC will investigate the breach’s timing, methods and scope with Arara, reporting the incident to relevant authorities.

Disclaimer: This news brief was created by Public Technologies (PUBT) using generative artificial intelligence. While PUBT strives to provide accurate and timely information, this AI-generated content is for informational purposes only and should not be interpreted as financial, investment, or legal advice. Sumitomo Mitsui Financial Group Inc. published the original content used to generate this news brief on November 05, 2026, and is solely responsible for the information contained therein.