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[Investigating][Severity: Major][Credential abuse]

West Japan Mitsubishi Motor Sales: unauthorized access to an employee Microsoft 365 mailbox may expose customer names, addresses and vehicles

An unauthorized login to an employee Microsoft 365 mailbox may have exposed customer names, addresses and vehicle details.

Disclosed

2026-10-30

Organizations involved

1

Leaked or at risk

Unknown

Downtime

Unknown

What happened

  1. The company disclosed that a third party had logged in without authorization to an employee Microsoft 365 account. [1]

Impact

The attacker could read past emails, so customer names, addresses and vehicle details in them may have gone outside. The number of people is not published. [1]

Response

The passwords of all accounts, including the affected one, were changed and no later unauthorized login has been seen. The company reported to the Personal Information Protection Commission. Mitsubishi Motors says similar cases are under way at its dealers. [1] [2]

Timeline

  1. Disclosed 2026-10-30
  2. 1 days

Attack or cause

Method
[Credential abuse]
Impact
[Data leak]
Entry point
Stolen credentials

Data exposed or at risk

[Name][Postal address]

Organizations involved

Open in organization search

Sources

  1. [1][Official]当社社員のメールアカウントへの不正アクセスについてのお知らせとお詫びWest Japan Mitsubishi Motor Sales · 2026-10-30
  2. [2][Official]当社販売会社における個人情報漏えいの可能性についてMitsubishi Motors · 2026-10-30