Sony Network Communications revealed a data breach impacting 2,585,481 customer records related to So-net and plala (S Course) internet services on October 27, 2026. The breach exposed personal information and passwords for 54,401 email addresses, while distinguishing them from primary membership passwords, which were not compromised. The affected database contained 2,141,986 So-net records and 443,495 plala (S Course) records.
Details disclosed included names, phone numbers, email addresses, user IDs, dates of birth, gender, and internet connection IDs.
Sony discovered unauthorized external access on October 19. The company continues investigating the cause and detailed impact; its notice does not identify an exploited vulnerability, attacker, or specific intrusion technique. The email credential exposure affected four services: Mail Service (G), with 24,655 addresses; A-Box additional mailboxes, totaling 17,672; So-net VAIO Mail, comprising 7,005; and PostPet Mail, with 5,069.
The affected individuals include 272,215 former So-net customers and 21,130 former plala (S Course) subscribers who canceled their subscriptions after March 2026.
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