Japanese media company Nikkei has disclosed another cybersecurity incident, revealing that attackers accessed approximately 1.83 million records stored in a cloud-based development environment. The discovery marks the third security breach reported by the company within roughly a month, following separate incidents involving employee email accounts.
Nikkei announced the latest breach on October 16, 2026, confirming that unauthorized access occurred during the early hours of October 7. Investigators determined that the attackers used stolen login credentials to enter a cloud system used for software development and access stored information.
Although the breach involved a substantial number of records, the company emphasized that most did not contain information that could directly identify individuals. Approximately 150,000 records included at least one personal detail, such as a name, email address, residential address, telephone number, or date of birth.
Email addresses appeared in roughly 120,000 records. The remaining 1.68 million records contained identifiers that could not independently identify individuals, while no credit card information was exposed.
After discovering the intrusion, Nikkei revoked the compromised credentials and began investigating the extent of the unauthorized access. The company notified Japan’s Personal Information Protection Commission on October 11 and said it would contact affected individuals directly.
As of October 16, investigators had found no evidence that the exposed information had been misused or published online. Nikkei also reported no signs of data manipulation, additional system compromise or disruption to its services.
The incident follows two previously disclosed account breaches. In late July, attackers accessed an employee’s Google Workspace account, potentially exposing personal information belonging to 1,646 employees and business partners.
A separate incident occurred in September when criminals compromised an employee’s Microsoft 365 account. On September 30, the attackers used the account to distribute approximately 9,000 phishing emails to company employees and external contacts, including people who had communicated with Nikkei journalists.
Nikkei has not identified the perpetrators behind the latest intrusion or established whether the three incidents are connected. The company is continuing its investigation and has promised additional security improvements.