楽天証券Data breach / unauthorized access incident
- Occurred on
- October 30, 2026
- Announced on
- October 31, 2026
- Severity
- AFinancial and HR records — information that easily translates into monetary damage.
- Scale
- 362 records
- Main impact
- A total of 362 records relating to purchasers of digital-benefit corporate bonds sold by 楽天証券 may have been taken out externally due to unauthorized access to a platform provided by NTTデータ's contractor. It is reported that authentication information such as login IDs and passwords were not included, but the specific leaked items are currently unknown and no fraudulent transactions have been confirmed.
- Information involved
- Full name
- Cause / key point
- Unauthorized access by a third party to the SaaS-type "デジタル証券プラットフォーム" provided by a contractor of NTTデータ.About Abuse of credentials
- Industry
- Finance & insurance
- Sources
- Last updated
- November 2, 2026
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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: Abuse of credentials(Logging in legitimately with leaked or guessed passwords)
Read the Abuse of credentials guide and national trends →