Kadokawa

Disclosed Jun 8, 2024254,241 affectedUnverified

BlackSuit ransomware attack on Kadokawa and Niconico leaks data of 254,241 people

Japanese publisher Kadokawa and its Niconico video platform were knocked offline by a ransomware attack on June 8, 2024 later claimed by BlackSuit, which leaked stolen data. Kadokawa said in August that information on 254,241 people was leaked, including 186,269 connected to its N High School online education institute.

What is known

People affected	254,241 (as reported by the organization)
Disclosed	Jun 8, 2024
Discovered	Jun 8, 2024
Attack	Ransomware
Data exposed	NamesEducation recordsEmploymentOther
Sector	Media · JP
Status	Unverified: not yet confirmed by an official notice, a filing or the organization

Sources

Newsenglish.kyodonews.net

Russia-linked group claims cyberattack on Japanese video site niconico

Newsasahi.com

More Kadokawa data leaked as deadline for ransom passes

Notices filed

TotalJun 8, 2024

Research254,241 people

History of this record

Added2026-09-25

First recordedby seedSource

First seen 2026-09-25 (Research). Record counts are as reported. Not legal advice.

Everything about Kadokawa