MUJI Data Breach: 1.09 Million Credit Card Numbers Exposed

As of November 4, 2026, Ryohin Keikaku, the company behind the MUJI brand, has reported a significant data security incident involving its official mobile application. An estimated 1.09 million MUJI Card credit card numbers may have been compromised due to unauthorized access to the platform.

Why it is trending now

The incident is trending as users seek clarity regarding the safety of their personal and financial information. The company issued a second follow-up report acknowledging that the scope of the leak likely includes full credit card numbers, prompting widespread concern among customers across Japan who use the MUJI app for shopping and loyalty rewards.

Key facts

• Approximately 1.09 million credit card records are potentially involved, according to reports from ITmedia and Yahoo! News.
• The breach stems from unauthorized access to the official MUJI app, as confirmed in the second official statement from Ryohin Keikaku.
• The exposed data includes full credit card numbers, which has elevated the severity of the security warning for affected users.

Why this is trending in Japan

MUJI is a ubiquitous retail brand in Japan, and the high volume of app users has led to significant public interest in the security of the platform. The news is trending as customers look for instructions on how to secure their accounts and monitor for potential fraudulent activity.

Background and context

The situation began with a report of unauthorized access to the MUJI system. While initial investigations were limited, subsequent findings confirmed the scale of the potential data exposure reached over one million records. Ryohin Keikaku is working to isolate the issue and has been communicating updates through their official channels to inform the public about the ongoing investigation into the unauthorized access.

What happens next

Ryohin Keikaku is continuing its investigation into the extent of the unauthorized access. Customers are advised to monitor their credit card statements for any suspicious transactions. Further information regarding support for affected users is expected to be provided by the company as the situation develops.