株式会社八十二長野銀行Data breach / unauthorized access incident
- Occurred on
- October 7, 2026
- Announced on
- October 19, 2026
- Severity
- BIncidents centered on names and contact details.
- Scale
- 672 records
- Main impact
- A staff email account was unlawfully accessed, and some email contents may have been viewed by third parties; information for 34 individuals, 627 corporations, and 11 other organizations, totaling 672 records, may be affected. No leakage of account numbers or PINs has been confirmed.
- Information involved
- Email addressPhone numberFull name
- Cause / key point
- A phishing email (a technique that exploits legitimate authentication functions) led a staff member to perform an authentication action, resulting in unauthorized access to the email account by a third party.About Targeted email & phishing
- Industry
- Finance & insurance
- Listing / capital
- Listed company東証プライム 8359(八十二長野銀行)
- Sources
- Last updated
- October 20, 2026
Stock price reaction to the disclosure八十二長野銀行 / 東証プライム 8359
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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
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Attack method classification: Targeted email & phishing(Fake emails and sites that steal credentials)
Read the Targeted email & phishing guide and national trends →