2025-11-28 Unauthorized Access to a System Under Development (Second Report)

As previously announced on November 14, 2025, unauthorized access to a new in-house service system that was under development might have resulted in some user information and usage data being leaked.

We are now able to inform you of the results of an investigation into the scope of the potentially leaked personal information. At this time, we have not confirmed any secondary damage, such as the publication of personal information on the Internet, as the result of this leak.

Potentially leaked personal information

(1)There are 934 user IDs that might have been leaked
These user IDs are limited to patrons who visited the Kansai-kan between March 15 and March 27, 2025.

(2)There are 40,373 requests for printouts of electronic materials from 4,360 individual patrons, containing information that might have been leaked
The following information regarding patrons who visited the Tokyo Main Library, the Kansai-kan, or the International Library of Children's Literature between September 24 and October 22, 2025, and who requested printouts of digitized materials, electronic journals, microform materials, or other electronic materials:

• User ID
• Name
• Information from requests for printouts of electronic materials:
• Title, URL, and National Diet Library Digital Collection material ID (persistent ID) of the requested material
• Sheet size, specification of color or monochrome printouts, and number of sheets printed
• Fee
• Purpose of request (investigation or research/other, and details)
• Facility where the printout was requested (Tokyo Main Library, Kansai-kan, or International Library of Children's Literature)
• Management number and room name of the library terminal used for the printout request
• Date and time of printout request
• Date and time of printout payment

Patrons who are affected will be notified individually. Please understand that we are unable to send individual notifications to patrons who have not registered their current contact information with us. If you believe you might have been affected and would like to know the status of your personal information, please contact us via the Inquiry Form on the NDL Website and be sure to select Others as the purpose of the inquiry.

Again, at this time we have not confirmed any secondary damage, such as the misuse of personal information that might have been leaked. Please do be cautious, however, and do not respond to suspicious phone calls or emails from parties that you do not recognize.

We sincerely apologize for any inconvenience or concern this matter might have caused to our patrons.