Sakura Internet Hack Exposes Up to 1.36 Million Accounts

Sakura Internet has disclosed that hackers accessed its sales management system on August 9, potentially exposing data from up to 1,360,563 member accounts. The Japanese cloud and data center provider discovered the breach while investigating a separate, less severe incident at its Sakura Rental Server service.

Hackers accessed customer contract and membership data. The sales management system stores member ID, company and division name, address, name, phone number, email address, date of birth, gender, FAX number, contract information, and billing details. According to the company's update on August 19, 2026, no data exfiltration has been confirmed, though the exact number of affected accounts remains under investigation.

ITmedia reports that hashed passwords for approximately 30 accounts may also have been accessed. The company states that stored passwords are hashed and should be difficult to decipher even if stolen.

The breach is separate from Sakura's core cloud services. Sakura Internet provides web hosting, VPS, public cloud, data-center colocation, and GPU computing services. It has been selected as a domestic provider for Japan's Government Cloud program, reducing the country's dependence on foreign hyperscalers. The compromised sales management system is distinct from its cloud infrastructure, and the company reports no operational or service disruptions.

A related Rental Server incident involved 583 accounts. Unauthorized logins occurred on that service, along with access to customer-facing systems, client data, and the installation of malware. Sakura Internet invalidated all abused credentials and removed the malware following that discovery. The larger sales system exposure came to light during the ongoing probe into the August 9 Rental Server breach, which predates its detection.

The company is notifying customers and authorities. Sakura Internet has informed relevant authorities of the incident and is individually contacting affected customers. It does not store credit card information in the compromised system. No ransomware or data extortion actor has claimed responsibility for the attack, and the precise type of malware involved has not been detailed.

The investigation continues into the full scope of the breach and any potential relation between the two incidents. Sakura Internet has not confirmed any misuse of the viewed data.