TV Asahi Mediaplex: unauthorized access to a server may have leaked 4,543 personal data records of employees, applicants and individual business partners, including My Number

Unauthorized access to a TV Asahi Mediaplex server may have leaked 4,543 personal data records, including My Number of 1,343 current and former employees.

Disclosed

2026-07-03

Organizations involved

Leaked or at risk

4.5K

4,543

Downtime

Unknown

What happened

2026-04-28
Around midnight it found that it may have been hit by a cyberattack. It stopped the servers involved, cut the outside network and investigated with outside experts. [1]
2026-06-19
It learned that some information may have leaked. [1]
2026-07-03
It announced the unauthorized access. [1] [2]
2026-07-30
In a second report after the investigation ended, it listed the personal data that may have leaked: 1,343 records of employees (former ones included), 2,786 of job applicants and 414 of individual business partners. The likely cause is theft and abuse of credentials of an account used for authentication. No secondary harm has been reported. [1] [3]

[Breached][Major]Tokyo, MinatoInformation and communications4,543 leaked
TV Asahi Mediaplex Inc.
Credentials of an account used for server authentication may have been stolen and abused, and files holding data such as the My Number of employees, former ones included, may have leaked.

						Note
TV Asahi Mediaplex Inc.	[Breached]	[Major]	Tokyo, Minato	Information and communications	4,543	Credentials of an account used for server authentication may have been stolen and abused, and files holding data such as the My Number of employees, former ones included, may have leaked.