Unauthorized external access to the membership database of Sony Group internet service provider So-net exposed more than 2.58 million personal information records belonging to current and former members. The affected data also includes 440,000 records for Docomo Hikari users whose service it operated under contract.

Key points

What happened: Unauthorized access to So-net's membership database exposed more than 2.58 million personal information records, including 54,401 email passwords.

Who is affected: Alongside current and former So-net members, 443,495 records for Docomo Hikari plala (S Course) users were exposed. Those who canceled by the end of February 2026 are excluded.

What to do: Affected email service users' passwords have been forcibly reset and need to be set again through So-net My Page.…