Reported breach

Yamada Denki data breach

JPJapan · ヤマダデンキ

ビジネス+IT reported a data breach at Yamada Denki (Japan) on 14 November 2026. It affected 3,500,000 customers.

What we know as of 15 November 2026

Status: Reported by ビジネス+IT; not yet confirmed by Yamada Denki or an authority.
People affected: 3,500,000 customers.
What was exposed: Phone numbers, Names, Addresses, Renovation history and Quotation data.
When: First reported 14 November 2026.
How: Hacking.
Yamada Denki’s record: No earlier breach on record under this name.

Not known yet: when it began and who was behind it. This page is updated as notices and statements come in.

Every fact above has its source below. Journalists: free to quote with credit (“Privacy Unpacked data breach tracker”, with a link to this page and the date); the figures can move. Follow this breach (feed) · Every major breach · Ask us for a figure

People affected: 3,500,000customers
Reported: 14 November 2026News report

What was exposed 5

Phone numbers
Names
Addresses
Renovation history
Quotation data

How it happened

How: Hacking Reformation management system suffered unauthorized access source
Our translation from Japanese
リフォーム管理システムが不正アクセスを受け

Sources 1

News reportビジネス+ITヤマダデンキでリフォーム顧客最大350万件漏えいか住所に施工履歴 ...14 November 2026 · 3,500,000 customers

News reports are read by an AI model; every fact taken from an article was checked word for word against it, and anything it could not find was dropped. · Corrections and changes

If Yamada Denki had your data

Look for Yamada Denki’s own notice or letter: it should say what of yours was involved. Keep it.
Your phone number is out: ask your mobile operator for a PIN or port-out lock, so nobody can move your number to another SIM card and take your login codes.
Your home address is out: be wary of letters, parcels or visitors that mention Yamada Denki, and of texts asking for a “delivery fee”.
Expect scams that use your details: calls, texts or emails pretending to be Yamada Denki, your bank or the police. Never give codes or passwords, never approve a sign-in you did not start, never move money.

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Questions about the Yamada Denki breach

Was Yamada Denki hacked?

ビジネス+IT reported a data breach at Yamada Denki (Japan) on 14 November 2026. It affected 3,500,000 customers. How it happened, by the sources: hacking. It has been reported but not confirmed by Yamada Denki or an authority.

What data was exposed in the Yamada Denki breach?

Phone numbers, Names, Addresses, Renovation history and Quotation data, by the notices and reports on this page.

How do I know if I was affected?

Organisations normally tell the people whose data was involved, by letter or email, and that notice says what of yours was in it. We cannot look up individual people. If you got a notice, check that it is real, then follow the steps on this page.

Is there a Yamada Denki data breach settlement?

No settlement open for claims is on record for Yamada Denki as of 15 November 2026. Every open settlement is listed with its deadline.

Is a letter, email or text about the Yamada Denki breach real or a scam?

A real notice names the breach, says what data was involved and never asks for a password, a code or a payment. Criminals often send fake notices after a breach is in the news. Do not use links or phone numbers in the message: go to Yamada Denki’s own site, or check the letter here.

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From the data breach tracker: official notices, breach databases and the news, every fact with its source. Open data (CC BY 4.0) · How the tracker works · Official registers · Corrections and changes · Accuracy audit · For journalists · Found a mistake? Tell us and we correct it.