楽天モバイル（my 楽天モバイルの支払い証明書）Data breach / unauthorized access incident
- Occurred on
- Unconfirmed
- Announced on
- October 13, 2026
- Severity
- AFinancial and HR records — information that easily translates into monetary damage.
- Scale
- Unknown
- Main impact
- It was announced that, due to a special operation, third parties' payment certificates (name, address, phone number, data usage, charges, etc.) could have been viewed. Actual viewing has not been confirmed. The fix was implemented on 2026年6月20日.
- Information involved
- Phone numberHome addressFull name
- Cause / key point
- Cause is under investigation.
- Industry
- IT & telecom
- Listing / capital
- UnlistedParent company: 楽天グループ(東証プライム 4755)
楽天モバイル is a subsidiary of 楽天グループ.
- Last updated
- October 20, 2026
Stock price reaction to the disclosure楽天グループ・親会社 / 東証プライム 4755
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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:
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Attack method classification: Under investigation / not stated(Cause not disclosed)
Read the Under investigation / not stated guide and national trends →