Benesse customer data leak
Add to my breach checkMade public · 35,040,000 records after merging duplicates
What leaked8
Hard to replace
- Mobile number
- Home or delivery address
- Email address
- Other profile data
Permanent
- Health information
- Date of birth
- Full name
- Gender
- Health informationexpected delivery date, users of some services only
- Mobile numberphone number · type not stated; fax number for registered users
- Home or delivery addresspostal code and address
- Email addressusers of some services only
- Full nameregistered user and their child or guardian
- Other profile datafamily relationship between registered user and child or guardian
To-dos5 · about 1 h 30 min in all
- If threatened: do not pay, keep the messages, report it to the policeLimits harm from: extortion
- Know the scam pattern: calls and texts that cite these leaked detailsLimits harm from: scam calls, phishing messages
- Turn on instant transaction alertsHelps you notice: scam calls
- Remove your address and phone from public profiles and tighten SNS privacyLimits harm from: visits or contact at home
- Use an authenticator app or passkey instead of SMS codesLimits harm from: SMS code theft
What happened next27 events
- Benesse Corporation and its group IT company ordered, jointly, to pay 3,300 yen to each successful plaintiff in five consolidated suits; other claims dismissed
- On remand, the Osaka High Court found a privacy infringement and ordered Benesse to pay 1,000 yen
- On appeal from a first-instance ruling that had found negligence but no compensable distress, the Tokyo High Court ordered Benesse Corporation and Synform, the company it had entrusted with managing the data, jointly to pay 2,000 yen to each of the two plaintiffs
- Group IT company held liable to 462 plaintiffs: 3,300 yen each · 3,000 yen solatium plus 300 yen legal fees; claim against Benesse dismissed
- Claim by about 180 customers dismissed: negligence found but no compensable distress · the 500 yen voucher was considered
22 more
- Supreme Court held the leak infringed the plaintiff's privacy and sent the damages claim back to the Osaka High Court
- On appeal the sentence was reduced to 2 years 6 months in prison and a 3 million yen fine
- The former contractor engineer was sentenced to 3 years 6 months in prison and a 3 million yen fine · Unfair Competition Prevention Act
- JIPDEC revoked Benesse's PrivacyMark certification, citing failures in contractor supervision and safeguards
- Submitted an improvement report to METI with a contractor-inclusive protection structure and security schedule
- Established an information security monitoring committee with outside experts
- METI recommendation under the Personal Information Protection Act: failure to supervise the contractor · Art. 22; urged thorough contractor supervision
- Published the summary of the external investigation committee's report: 216.39M gross records, about 35.04M after merging, about 48.58M people
- From mid-September, apology letters offered a 500 yen voucher · e-money gift or book card
- Set up a dedicated customer support division
- The vice chairman (representative director) and a director/CIO resigned over supervisory responsibility
- Q1 results booked a 26 billion yen extraordinary loss for investigation and security costs; forecast withdrawn
- Set aside a 20 billion yen fund for apologies to customers · gifts, fee reductions under consideration
- Filed a criminal complaint with the Tokyo Metropolitan Police; a contractor's former employee was arrested on 17 July
- From 12 July, letters of apology and explanation sent to customers whose data was confirmed leaked
- METI ordered Benesse to report under the Personal Information Protection Act · Art. 32
- Held a press conference on the leak
- Benesse confirmed the leak was its own and began work against suspicious solicitation; it asked businesses it judged likely to be using the data to stop
- Free-dial customer inquiry line opened after the 9 July press conference
- Reported the situation to METI and consulted it on next steps
- Customer inquiries led Benesse to suspect a leak; an emergency task force and internal investigation started
- Intrusion began
- Company
- Benesse Corporation
- When it happened
- –
- Company detected it
- Made public
- Notice
- Leak confirmed
- Affected
- 35,040,000 records after merging duplicates · about 28.95M estimated actual records; about 48.58M people
How the facts developed
- About 35.04 million records sold to three list brokers (about 28.95 million estimated actual); email and expected delivery dates added for some services; no card data found sold
- First announcement: 7.6 million records confirmed leaked, up to 20.7 million possible; names, addresses, phone numbers, children's gender and dates of birth
Sources
- Benesse Corporation company notice (opens in a new tab)checked October 22, 2026
- Benesse Holdings / Benesse Corporation company notice (opens in a new tab)checked October 22, 2026
- 東京地方裁判所 court (opens in a new tab)checked October 22, 2026
- 日本経済新聞 press, (opens in a new tab)checked October 22, 2026
- 日本経済新聞 press, (opens in a new tab)checked October 22, 2026
- Monolith Law Office press (opens in a new tab)checked October 22, 2026
- 政治山 press (opens in a new tab)checked October 22, 2026