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JAENES
SLeak confirmedOctober 28, 2026 announced

ENEOSパワー（ENEOSでんき・でんきサービスのお客さまページ）Data breach / unauthorized access incident

笹尾 祐太朗の写真Reviewed by Yutaro SasaoWritten by Leak Watch editorial team published ・ updated
Occurred on
October 19, 2026
Announced on
October 28, 2026
Severity
SCompromise of deep personal data or usable credentials.
Scale
57 people
Main impact
Unauthorized access to the customer pages of ENEOSでんき and でんきサービス resulted in the confirmation and disclosure that personal data for 57 people — names, addresses, login IDs, passwords, usage statements (usage amounts and billing amounts), customer numbers, etc. — were leaked externally. Bank account numbers and credit card numbers were not affected; individual notifications to affected persons and an investigation are underway.
Information involved
Full nameHome addressUser / member IDPassword
Cause / key point
Unauthorized access by a third party to customer pages (occurred 2026-10-19 19:04–10-20 05:11, discovered on 10-27); the intrusion route is under investigation.
Industry
Services & other
Listing / capital
UnlistedParent company (listed holding company): ENEOSホールディングス(TSE Prime 5020)

The incident entity, ENEOSパワー株式会社, is an electricity retail company under ENEOSホールディングス (TSE Prime・5020).

Sources
Last updated
October 29, 2026

Stock price reaction to the disclosureENEOSホールディングス・親会社(上場持株会社) / 東証プライム 5020

2026.10.08 〜 2026.10.29Loading…

Stock information is reference data based on Yahoo Finance and may be delayed. This site does not solicit or advise investment and does not guarantee the accuracy or completeness of this information. We accept no liability for any investment decision based on it.

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Written & reviewed

笹尾 祐太朗の写真

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: Unauthorized access (method undisclosed)(Breached, but the technique was not identified or disclosed)

Read the Unauthorized access (method undisclosed) guide and national trends →

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