Ryohin Keikaku (MUJI app)
Tokyo, Japan4 sources
Confirmed:Confirmed by the organisation, a regulator or a securities filing. First reported 30 Oct 2026.
MUJI app data leak may affect up to 27.26 million
Ryohin Keikaku disclosed on 30 October 2026 that data held in its MUJI app may have leaked, affecting up to about 27.26 million records including lapsed members. Exposed fields were email addresses, dates of birth and gender; card, name, address and phone data were not included.
- Type
- Data breach
- Sector
- Retail
- Records
- 27.3M records confirmed
- First reported
- 30 Oct 2026
- Latest source
- 30 Oct 2026
What to do
- If you have an account, change that password, and anywhere you reused it.
- Turn on two-factor authentication, ideally an authenticator app or passkey, not SMS.
- Expect phishing that uses your real details. Do not click links in messages about this incident; go to the company's site directly.
- If payment cards were involved, watch statements and ask your bank for a new card.
- If government ID or social security numbers were involved, consider a credit freeze.
- If this is a vendor of yours, ask what of your data they held and whether it was in scope.
- Reset any API keys, SSO trusts or shared credentials you have with them.
- Brief your help desk: attackers often impersonate the breached brand next.
Not sure? Ask an assistant with the sources attached, or have a coding agent check your systems.
Check your systems for Ryohin Keikaku (MUJI app)