Skip to content
JAENES
BPossible leakOctober 28, 2026 announced

ベネフィット・ワン（会員優待サービス「トクかい」、共同提供: クレディセゾン、業務委託先: フォレステック）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 14, 2026
Announced on
October 28, 2026
Severity
BIncidents centered on names and contact details.
Scale
29,465 people
Main impact
Due to unauthorized access to the system of contractor フォレステック that operates “トクかい”, it was announced that personal data for 29,465 members (including some former members) — name, furigana, date of birth, gender, postal code, email address, customer number, membership enrollment/withdrawal information, and the management number used for membership fee payment processing — may have been exposed. Some authentication-related information for ベネフィット・ワン used for payment system integration may also be at risk, but credit card numbers, expiration dates, and security codes are not included; トクかい has suspended its service and no misuse has been confirmed.
Information involved
Full nameDate of birthHome addressEmail addressUser / member ID
Cause / key point
Unauthorized access to the フォレステック system (occurred intermittently from 2026-10-14 to 2026-10-20, with additional detections on 24–25; root cause under investigation).About Supply chain attacks (via vendors & shared services)
Industry
Services & other
Listing / capital
Listed companyTSE Prime 3936(ベネフィット・ワン)

“トクかい” is a membership service jointly provided by listed company ベネフィット・ワン (TSE Prime・3936) and クレディセゾン.

Sources
Last updated
October 29, 2026

Stock price reaction to the disclosureベネフィット・ワン / 東証プライム 3936

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.

Where to go for this information

The steps themselves are on the protection guide. These links match the kinds of data in this incident, plus support contacts.

Ask AI about this incident

Opens an AI chat with this page's URL already in the prompt. Treat the answer as a starting point — always verify with the official sources listed above.

Ask ChatGPT ↗Search Perplexity ↗

Full nameDate of birthHome addressEmail addressUser / member IDHow severity is assessed →

Is this incident worth paying attention to?

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

Related incidents

Browse the database →

Incidents sharing the same company, service, attack method or industry (grouped automatically from the disclosures).

Incidents related to "クレジットカード"

Incidents where the damage spread through the same service or system.

Incidents related to "セキュリティコード"

Incidents where the damage spread through the same service or system.

Same attack method

Same industry

Attack method classification: Supply chain attacks (via vendors & shared services)(Compromising the provider instead of the user)

Read the Supply chain attacks (via vendors & shared services) guide and national trends →

← Back to Breach Watch