Independent Reporting · Not Legal or Security Advice · Verify With the Breached Company · Editorial Policy

KDDI Data Breach Exposes Up to 14.2 Million Customer Accounts Across Six Japanese ISPs

KDDI corporate headquarters building in Tokyo, Japan

KDDI Corporation, one of Japan’s largest telecommunications providers, disclosed a significant data breach on June 28, 2026, revealing that up to 14.22 million customer accounts may have been compromised. The breach, which also affected five partner internet service providers that rely on KDDI’s email infrastructure, exposed customer email addresses and passwords stored within the company’s … Read more

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