July 29, 2026 Measures (Guidance) to Protect the Secrecy of Communications to KDDI CORPORATION (hereinafter referred to as "KDDI")

　Today, the Ministry of Internal Affairs and Communications (MIC) issued written administrative guidance to KDDI, with President, Representative Director, CEO MATSUDA Hiromichi, concerning the leakage of confidential communications at KDDI. The document requests that KDDI take all necessary measures to ensure the protection of the secrecy of communications, implement necessary recurrence-prevention measures, and report on the implementation of these measures.

Note: The published materials are in Japanese only.

1　 Background, and other details

　KDDI reported that in the email system provided by KDDI to multiple Internet service providers, from May 16, 2026, to June 17, 2026, email-related information—including users’ email addresses and passwords used to log in to the email system—was leaked due to unauthorized external access. As a result, third parties who had stolen the passwords were able to view the contents of the mailboxes of approximately 7.62 million users (hereinafter referred to as the "Incident"). The Incident constitutes a leakage of secrecy of communications as stipulated in Article 4, Paragraph 1 of the Telecommunications Business Act (Act No. 86 of 1984).

2　 Details of measures

　The MIC deeply regrets that the Incident had a significant impact on users and severely undermined public trust in the telecommunications business. Accordingly, the MIC issued strict administrative guidance today to take thorough measures to prevent a recurrence.

　The MIC will continue to provide necessary guidance and supervision to ensure the protection of the secrecy of communications.