Notice Regarding Potential Cybersecurity Incident(Final Report)

March 27, 2026
HOSOKAWA MICRON CORPORATION

We sincerely thank you for your continued patronage and support.
As announced on Tuesday, February 3, 2026, and Monday, February 16, 2026 (*), we confirmed an incident that may indicate a cyberattack on Monday, February 2, 2026, at approximately 10:00 AM (JST) (hereinafter referred to as "this incident"). Subsequently, on Sunday, February 15, 2026, we confirmed that electronic files suspected to have been leaked from our systems due to this incident were published on the Internet.

(*) February 3, 2026:   https://www.hosokawamicron.co.jp/en/news/2026/0203.html
(*) February 16, 2026: https://www.hosokawamicron.co.jp/en/news/2026/0216.html

Since the occurrence of this incident, we have been investigating the cause and scope of damage with the cooperation of external specialists. The investigation by external specialists has now been completed, and we would like to inform you of the results as follows. We sincerely apologize for any inconvenience and concern this situation has caused for all parties involved.

1. Overview of This Incident

On Monday, February 2, 2026, at approximately 10:00 AM (JST), we confirmed an incident that may indicate a cyberattack.
Immediately after confirming this incident, we took necessary measures such as restricting external access, and with the cooperation of external specialists, we investigated the cause and scope of damage. On Sunday, February 15, 2026, we confirmed that electronic files suspected to have been leaked from our systems due to this incident were published on the Internet.
As a result of the investigation, unauthorized access to one account on a cloud storage service that we used on a supplementary basis (hereinafter referred to as "the Service") was confirmed, and it was found that files stored on the Service, including personal data described in section 2 below, had been leaked.
We have reported this incident to the police, the Personal Information Protection Commission, and other relevant authorities.

2. Personal Data Leaked Externally

*We will notify affected individuals sequentially.
For those whom we cannot contact individually, this public announcement will serve as notification.

3. Cause

It is believed that the attacker gained unauthorized access to one account on the Service using a leaked or guessed ID and password.

4. Secondary Damage

To date, we have not received any reports of secondary damage such as unauthorized use of personal data.

5. Recurrence Prevention Measures

We had previously established internal regulations regarding information security, introduced security software to prevent unauthorized access, and implemented measures to properly manage the information we handle. However, we take this situation very seriously and based on the investigation results and advice from external experts, we will strengthen our system security and monitoring systems to prevent recurrence.

6. Impact on Business Performance

There has been no business interruption due to this incident, and the impact on business performance is minimal.

Once again, we sincerely apologize for any inconvenience and concern this has caused to all parties involved.
If you have any questions regarding this matter, please contact our "Inquiry Contact" below.

■ Inquiry Contact
HOSOKAWA MICRON CORPORATION
Email: contact_prt@hmc.hosokawa.com