There were 126 articles related to data breaches in August 2026. Unauthorized access was the most common cause, accounting for 97 cases, while the largest incident reportedly involved the leakage of 8,853,839 records at ShopServe. Reports of arrests, disciplinary actions and administrative guidance measures totaled 12, or approximately 10% of the cases.
The number of articles increased from July this month, and unauthorized access reportedly accounted for the majority of the incidents’ primary causes. System management errors followed with 10 cases, while unauthorized removal accounted for 4 cases, bringing the total number of articles covered to 126.
August also saw incidents ranking among the largest in terms of the scale of damage, with multiple cases involving more than 1 million records among the top 5. In particular, the number-one incident, involving 8,853,839 records, reportedly concerned the external transmission of purchaser information through unauthorized access to ShopServe. Additional leakage related to アスクル’s ransomware incident was also reported.
A total of 7 cases involving leaked card information were reported in August, including a case in which the card information of 24,166 people reportedly leaked from インシデックス. Among these, the incidents involving インク革命, ファインオンラインショップ and 虫退治ドットコム reportedly resulted in prompt disclosure and response.
A total of 12 arrests and disciplinary actions were reported in August, and measures taken in connection with data breaches and other incidents are reportedly on the rise. Overall, it has been noted that large-scale data breaches are attracting public attention and that disclosure of the resulting measures is progressing.