スタディサプリData breach / unauthorized access incident
- Occurred on
- Unconfirmed
- Announced on
- October 3, 2026
- Severity
- CLimited data such as email addresses and identifiers.
- Scale
- 3,687 records
- Main impact
- For 3,687 email addresses, a third party may have been able to verify whether they were registered with スタディサプリ. No data leak has been confirmed at this time, but there is concern about registration identification.
- Information involved
- Email address
- Cause / key point
- Unauthorized access by a third party exploiting a specification flaw in part of the system's functionality.
- Industry
- Education
- Listing / capital
- UnlistedParent company: リクルートホールディングス(東証プライム 6098)
スタディサプリ is a service of リクルート.
- Sources
- Last updated
- October 20, 2026
Stock price reaction to the disclosureリクルートホールディングス・親会社 / 東証プライム 6098
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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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Other incidents at スタディサプリ
Same attack method
- SSソースネクスト2026.10.15 announced・Affected 22,519,960 records
- SSバーガーキング・ジャパン(公式アプリ)2026.10.15 announced・Affected 11,180,000 records
- SS焼肉きんぐ2026.10.05 announced・Affected 10,788,963 records
- Bユミルリンク（メール配信システム）2026.10.19 announced・Affected 9,000,000 records
- SSタイムズカー(タイムズモビリティ)2026.09.25 announced・Affected 6,600,000 accounts
- Sブックオフグループ(ブックオフコーポレーション)2026.10.09 announced・Affected 6,383,279 people
Same industry
- Sちとせグループ（ちとせアカデミー）2026.10.09 announced・Affected 843 people
- S山口大学（教職員メール）2026.10.06 announced・Affected 1 accounts
- S大阪公立大学2026.10.05 announced・Affected Unknown
- S日本エネルギー経済研究所2026.10.02 announced・Affected 13 records
- S日本原子力研究開発機構（研究支援サイト）2026.10.01 announced・Affected 175 people
- S大阪市立小学校（成長・肥満度曲線）2026.09.09 announced・Affected 18 people
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 →