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Unauthorized access to Yamada Denki's renovation management system (up to 3.5 million records): names, addresses, phone numbers, renovation history and quotes may be affected — what customers should do

Yamada Denki says unauthorized access to its renovation system may have affected up to 3.5M records. Whether data leaked is under investigation.

Published 2026-11-15 Updated 2026-11-15 Last verified 2026-11-15 8 min read

On this page

For: customers who have asked Yamada Denki for a renovation or a renovation quote. This article is an explanation based on Yamada Denki's official notice and does not cover attack methods.

Bottom line

a leak is not confirmed yet, but do not respond to contacts posing as Yamada Denki, and treat any request for a password or PIN as fake

According to Yamada Denki's notice, the unauthorized access to its renovation management system may have affected the names, addresses, phone numbers, renovation history and quotation data of up to 3.5 million records. Credit card information and My Number are not included. Whether customer information was leaked outside is under investigation.

Be wary of emails, texts and calls posing as Yamada Denki, and do not open their links
The company says it never asks for passwords or PINs by email or phone
To check, contact the official customer consultation desk yourself (0120-335-537, Japan)
When updates arrive (whether a leak occurred, how affected customers are contacted), the table in this article will be updated

Developing: this article will be updated as the organisation publishes more

Who is affected: customers who have asked Yamada Denki for a renovation or a renovation quote.
Confirmed so farSee the table ↓: Unauthorized access and blocking
Cause
Listed as possibly affected
Number of records
Name, address, phone number
Renovation history, quotation data and other sales records
Not yet confirmed: Whether customer information was leaked outside
Cause (how the access happened)
Final number of records (up to 3.5 million)
2 more
How affected customers will be contacted
Whether the data has been misused
What to do nowSee the steps ↓: Do not respond to contacts posing as Yamada Denki
Treat requests for a password or PIN as fake
If in doubt, contact the official desk
1 more
If you entered information or sent money, get help right away
Where to verify (source)All sources ↓: Yamada Denki, "Apology and notice regarding the discovery of unauthorized access to our renovation management system" (November 13, 2026, PDF, in Japanese)
Last checked: As of November 15, 2026

Follow-up plans and what we checked

The company says the investigation into whether customer information was leaked outside is continuing and that it will announce further developments. It adds that it will continue to investigate the scope and cause and will announce promptly when new information is confirmed. On November 15, 2026, we checked the notices page of Yamada Holdings and found no update after the November 13 notice.

What customers should do today

Do not respond to contacts posing as Yamada Denki

The company asks customers to be careful with emails, text messages and calls pretending to be the company. If you receive a message you do not recognize, do not open its links or attachments and do not enter personal information. See What is phishing for how to spot one.

A sender who knows your name, address and phone number, and even your renovation history or quote, will generally look genuine (our view). Do not use links in the message. Open the official site yourself or call an official contact to check.

Treat requests for a password or PIN as fake

The company says that it never asks for passwords or PINs by email or phone. Do not answer such a request, even if it is described as identity verification.

If in doubt, contact the official desk

The customer contact in the notice is the Yamada Denki customer consultation desk: phone 0120-335-537 (10:00 to 18:00, except January 1) and email customer.hotline@yamada-denki.jp. A separate contact exists for the press.

The notice does not say how to check whether you are affected. Use a contact on the official notice, not a number in an email or text message.

If you entered information or sent money, get help right away

If you entered personal information on a suspicious page or sent money, contact your bank or card company at once. In Japan you can also call the police consultation line (#9110) or the Consumer Hotline (188). For unusual activity on an account, see How to check for unauthorized access.

What happened (from Yamada Denki's notice)

On November 13, 2026, Yamada Denki published "Apology and notice regarding the discovery of unauthorized access to our renovation management system" (also posted on the Yamada Holdings notices page). Everything below is from the company's notice.

November 12
Unauthorized access to the renovation management system was confirmed. Access from outside was blocked immediately and a detailed investigation began.
November 13
The apology and notice were published. The company says whether customer information was leaked outside is still under investigation and that it will announce further developments.

Up to 3.5M

Records of personal information that may have been affected (company; an upper figure)

Under investigation

Whether customer information was leaked outside (company)

Not included

My Number, credit card information

Out of scope

Information unrelated to renovation (store and online shop appliance purchases, etc.)

Key points of the notice (November 13, 2026)

Confirmed: November 12, 2026 (unauthorized access to the renovation management system)
Number of records: Up to 3.5 million (may have been affected)
Information that may have been affected: Personal information of customers registered in the system: name, address, phone number and other sales records such as renovation history and quotation data
Not included: My Number and credit card information. Information unrelated to renovation (appliance purchases in Yamada Denki stores or on its online shop, etc.) is out of scope
Cause: Unauthorized access by a third party (route and method not disclosed)
Contact: Yamada Denki customer consultation desk 0120-335-537 (10:00 to 18:00, except January 1)

What is known and not known

This table summarizes the company's notice of November 13 as of November 15, 2026. The company presents the items below as personal information that may have been affected. We will update the status column when more is published.

Item	What the notice says	Status
Unauthorized access and blocking	Confirmed on November 12; access from outside blocked immediately	Confirmed (company)
Number of records	Up to 3.5 million	Possible (company; an upper figure)
Name, address, phone number	Included in the information that may have been affected	Possible (company)
Renovation history, quotation data and other sales records	Included in the information that may have been affected	Possible (company)
Leak of customer information outside	Still under investigation	Under investigation (company)
My Number, credit card information	Not included	Not included (company)
Information unrelated to renovation (store and online shop appliance purchases, etc.)	Out of scope	Not included (company)
Email address	Not listed as an item (the contents of "other sales records such as renovation history and quotation data" are not detailed)	Not stated
Cause	Unauthorized access by a third party	Confirmed (company)
Route and method of the access	Not described	Not stated
Misuse	No report of misuse found; the company urges caution about suspicious contacts	Not stated
Individual notification	Not described	Not stated

What can happen with names, addresses, phone numbers and renovation history

The table below describes what can generally happen with combinations of these items. It does not mean any of it has happened in this case.

Information that may have been affected	What can generally happen	What customers can do
Name + phone number	Convincing calls or texts in Yamada Denki's name	Call back only through an official contact
Name + address	Mailings or visits, or fake invoices	Do not pay an invoice you do not recognize; check with an official contact
Renovation history and quotation data	Contacts that seem to know the work, offering inspections, extra work or warranties	Do not sign or pay on the spot; check with an official contact

What can happen with the information that may have been affected

Convincing emails, texts and calls posing as Yamada Denki
Offers of extra work or inspections that seem to know your renovation
Requests for a password or PIN under the name of identity verification

What the notice says is out of scope

My Number
Credit card information
Information unrelated to renovation (appliance purchases in stores or on the online shop, etc.)

Sources (public records)

The facts in this article are based on the following official notice. We have not speculated about details that were not disclosed.

Yamada Denki, "Apology and notice regarding the discovery of unauthorized access to our renovation management system" (November 13, 2026, PDF, in Japanese) — yamada-holdings.jp
Yamada Holdings notices page (to confirm the posting) — yamada-holdings.jp

Update history

2026-11-15: First published, based on Yamada Denki's notice of November 13. We checked the official notices page the same day and found no follow-up.

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FAQ

QWhat may have been affected in the Yamada Denki incident?

According to Yamada Denki's notice of November 13, 2026, the name, address, phone number and other sales records such as renovation history and quotation data of customers registered in the renovation management system may have been affected by the unauthorized access. Up to 3.5 million records are in scope.

QAre credit card details or My Number included?

The company says My Number and credit card information are not included. Information unrelated to renovation, such as appliance purchases in Yamada Denki stores or on its online shop, is also outside the scope.

QWas the data actually leaked?

The notice confirms that the system was accessed without authorization, but says that whether customer information was leaked outside is still under investigation. The listed items are described as information that may have been affected; the notice does not say a leak was confirmed.

QIs the cause known?

The notice says the renovation management system was accessed without authorization by a third party. How the access happened is not described.

QHow can I find out whether I am affected?

The notice does not describe how affected customers will be contacted. If you want to check, contact the Yamada Denki customer consultation desk listed in the notice (phone 0120-335-537, 10:00 to 18:00, except January 1; a Japanese number). Use the contact on the official site, not a number in an email or text message.

QWhat should I do if someone contacts me in the name of Yamada Denki?

The company asks customers to be careful with emails, text messages and calls pretending to be the company, and says it never asks for passwords or PINs by email or phone. Do not open links in suspicious messages and do not enter personal information.