エネサンスグループData breach / unauthorized access incident
- Occurred on
- October 21, 2025
- Announced on
- May 11, 2026
- Severity
- AFinancial and HR records — information that easily translates into monetary damage.
- Scale
- 365,000 records
- Main impact
- About 約36.5万件 of customer contact details and other records, along with employee information, were confirmed to have been published by the attacker.
- Information involved
- Not specified in the disclosure
- Cause / key point
- A cyberattack involving ransomware.About Ransomware
- Industry
- Services & other
- Listing / capital
- Unlisted
- Sources
- 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
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Attack method classification: Ransomware(Encrypting data and demanding a ransom)
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