日本大学（学生・卒業生メール）Data breach / unauthorized access incident
- Occurred on
- June 24, 2026
- Announced on
- July 6, 2026
- Severity
- SCompromise of deep personal data or usable credentials.
- Scale
- 9 people
- Main impact
- Email accounts of a total of 9 current students and alumni were illicitly used by a third party, and as of July 3, 17,864 suspicious emails had been sent. There is a risk that email contents and personal information were accessed.
- Information involved
- User / member IDPassword
- Cause / key point
- Unauthorized logins to email accounts by a third party were confirmed.About Abuse of credentials
- Industry
- Education
- Listing / capital
- Non-profit corporation
Private university (non-profit)
- Last updated
- October 20, 2026
Is this incident worth paying attention to?
Written & reviewed
Reviewed byYutaro SasaoFounder & CEO, MediaLeap Inc.
CEO of MediaLeap Inc. Working on both sides of web advertising and web media since 2013; founded the company in May 2025.
Review scope: cross-checking against primary sources (official and government announcements), verifying claims stay within the facts, and checking source attribution。Last reviewed:
Written by:Leak Watch editorial team (AI-assisted drafts verified against sources by the editorial team) · Reviewer profile · Request a correction
Related incidents
Browse the database →Incidents sharing the same company, service, attack method or industry (grouped automatically from the disclosures).
Incidents related to "メールアカウント"
Incidents where the damage spread through the same service or system.
- B株式会社八十二長野銀行2026.10.19 announced・Affected 672 records
- Sエバーグリーン・マーケティング（メール）2026.10.06 announced・Affected 763 records
- S山口大学（教職員メール）2026.10.06 announced・Affected 1 accounts
- B日経BP2026.10.04 announced・Affected 26 records
- S講談社BECK（旧ビーシーのメール）2026.10.02 announced・Affected 1 records
- B大気社（マレーシアグループ会社）2026.09.18 announced・Affected 1 accounts
Same attack method
- A日本経済新聞社(日経)2026.10.16 announced・Affected 1,830,000 records
- Sチャーム本店2026.09.01 announced・Affected 370,000 records
- ACAMPFIRE2026.06.02 announced・Affected 225,846 accounts
- Aウエーブ（Webアップロード）2026.04.01 announced・Affected 176,810 records
- Aシチズン時計（問い合わせ管理）2026.10.06 announced・Affected 100,000 people
- Bイノベーション（GitHub）2026.08.07 announced・Affected 62,689 people
Same industry
- Sちとせグループ（ちとせアカデミー）2026.10.09 announced・Affected 843 people
- S大阪公立大学2026.10.05 announced・Affected Unknown
- S日本エネルギー経済研究所2026.10.02 announced・Affected 13 records
- S日本原子力研究開発機構（研究支援サイト）2026.10.01 announced・Affected 175 people
- S大阪市立小学校（成長・肥満度曲線）2026.09.09 announced・Affected 18 people
- S東京都立大学（教員のGoogleアカウント）2026.01.08 announced・Affected 423 records
Attack method classification: Abuse of credentials(Logging in legitimately with leaked or guessed passwords)
Read the Abuse of credentials guide and national trends →