Notice Regarding Potential Leak of Personal Information Due to Unauthorized Access at RAKUS Light Cloud Co., Ltd.

Japan Petroleum Exploration Co., Ltd. (JAPEX) hereby announces that unauthorized access by a third party occurred within the services provided by RAKUS Light Cloud Co., Ltd. (RAKUS Light Cloud), which JAPEX uses for information distribution, and that personal information managed by JAPEX may have been leaked externally. We regret any concern or inconvenience this may cause to those affected and all other parties concerned.

1. Background

JAPEX uses "blastmail," an ASP service provided by RAKUS Light Cloud, as a distribution tool for the "JAPEX Newsletter" --which notifies subscribers of new materials and content updates on our website--as well as for sending event invitations to institutional investors and securities analysts.
On October 21, 2026, JAPEX received a report from RAKUS Light Cloud stating that personal information registered with their service may have been leaked externally.

2. Affected Personal Information and Maximum Number of Items

• Information of subscribers to the JAPEX Newsletter (the number of registered records is currently under investigation)
  ・Email address
• Information of recipients of event announcements for institutional investors and securities analysts (the number of registered records is currently under investigation)
  ・Name, company name, department, job title, email address, postal code, address, and phone number

Please note that, as of now, there is no confirmed evidence that any of this personal information has been misused.

3. Response to Affected Individuals and Parties

"blastmail" is an external cloud service that operates independently of our systems. This incident has had no impact on our networks, systems, or business operations.

4. Future Actions and Measures

Should any new facts come to light, we will promptly disclose them as necessary. If we confirm that personal information has been leaked, we will contact the affected individuals directly to explain the circumstances of the incident and provide guidance on steps to prevent further harm.