Kissei Pharmaceutical Co., Ltd. group company キッセイ商事 announced unauthorized access by a third party, and an email notifying recipients of data theft was sent on the night of 7 October. The possibility that sensitive personal information was leaked could not be ruled out, and an investigation into the route of the leak and the scope of the damage is under way with external experts.
At around 21:50 on 7 October 2026, an email notifying personnel associated with キッセイ商事 of data theft was sent, and measures including immediately blocking access were taken after unauthorized access was confirmed. The company is investigating the route and cause of the information leak and the scope of the actual damage in cooperation with external experts.
According to the announcement, the possibility that sensitive information, including personal information requiring special care, had been leaked could not be ruled out. The types of information involved and the number of affected people have not been disclosed. Kissei Pharmaceutical Co., Ltd. is also investigating the potential impact on entities other than キッセイ商事, but no unauthorized access to the core system has been announced.
The company also outlined a policy of standardising security standards across the group and visualising risks, with SecureNavi株式会社 providing support. No system disruption has been confirmed at this time, and the company plans to announce any new findings through an official release.