NTT docomo probes breach; up to 300,000 customer records may leak

NTT docomo said on November 5, 2026 that unauthorized access to the servers of docomo Online Shop and My docomo had been confirmed, and that up to about 300,000 customer records may have been leaked, according to gamebusiness.jp.

The company detected the unauthorized access to both services on November 4. It suspended various procedures and began emergency maintenance from around 1:05 on November 5.

The information potentially exposed includes names, addresses, dates of birth, mobile phone numbers and contact phone numbers. docomo said the exact scope and detailed number of affected records are still under investigation, and that it will contact affected customers individually once they are known. No new leaks have been confirmed since the maintenance began.

Cause and service resumption undecided

The cause and intrusion route of the unauthorized access are still being identified, and no resumption date has been set for docomo Online Shop or My docomo.

docomo warned customers not to open links or files in suspicious emails, SMS messages or calls claiming to come from the company or related parties.

Separately, a communications failure affecting 5G SA subscribers occurred from around 11:18 on November 5. docomo said no traces of unauthorized access or signs of a cyberattack were confirmed in connection with the failure, and did not mention any link to the data leak.