Investigating

Mynavi: user, partner and employee data may have leaked via cloud-service intrusion

After detecting an anomaly on a used cloud service on 5 Dec 2025 and confirming possible personal-data exposure on 16 Jan 2026, Mynavi issued a first notice on 12 Feb and later updates with category counts.

Last updated: 2026-11-09

Overview

Third-report categories: 74,224 general users, 21,609 corporate contacts, 15,672 employees—not summed (count blank). No cards or My Numbers. Not an intrusion into Mynavi service databases.

Timeline

  1. Occurred
  2. Discovered
  3. Disclosed

Organization response

Per the notice, the organisation investigated and contained the incident, notified individuals and offered monitoring or protective resources.

What you can do

Be wary of emails, SMS or calls impersonating the organisation; do not open links or attachments or enter passwords or card details. Change reused passwords on other services.

Sources

  1. (第三報)当社が利用するクラウドサービスに対する不正アクセスの発生および個人情報流出の可能性について株式会社マイナビ · 2026-11-09
  2. 当社が利用するクラウドサービスに対する不正アクセスの発生および個人情報流出の可能性について株式会社マイナビ · 2026-11-09
  3. (第二報)当社が利用するクラウドサービスに対する不正アクセスの発生および個人情報流出の可能性について株式会社マイナビ · 2026-11-09

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