Advantest’s U.S. entity disclosed that some data, including personally identifiable information, had been taken from its servers in a February 2026 cyberattack and submitted a data breach notification to the State of California.
On 19 February 2026, Advantest detected anomalous activity on its network, isolated the affected systems and disclosed the possibility of unauthorized access by a third party and ransomware deployment. At the initial response stage, the scope of the impact was considered limited, and core operations including production, shipping and customer support remained operational.
According to the notification published in October, some data was extracted from the servers, and it was confirmed that the personally identifiable information of individuals covered by the notification was included. The number of affected individuals has not been disclosed, but possible data types included SSNs, government-issued IDs, financial information and medical information.
To prevent the incident from spreading, potentially affected systems were isolated, while additional system shutdowns and monitoring continued. The company worked with external specialists and investigative authorities to restore the network and strengthen controls. Kroll is expected to provide 18 months of credit and web monitoring to support affected individuals.
No disclosure or confirmed misuse of personal information has been identified at this time, and instructions on activating the services will be available through 4 January 2027. Further investigations and additional notifications may follow.