Business SaaS and e-mail

Shisho Cloud download and preregistration forms

Shisho Cloud download and preregistration forms (run by GMO Flatt Security Inc.) was hit in 1 recorded cybersecurity incident. The latest was disclosed on 2026-10-16.

About the service

Website

https://shisho.dev/

Run by

GMO Flatt Security Inc.

Category

Business SaaS and e-mail

For

Businesses

Incident history

Disclosed 2026-10-16Updated 2026-11-05Aichi, Aomori, Chiba, Fukuoka, Fukushima, Gifu, Hiroshima, Hokkaido, Kagawa, Kagoshima, Kanagawa, Kochi, Kyoto, Mie, Miyagi, Nagano, Nagasaki, Niigata, Okayama, Okinawa, Saitama, Shiga, Tokyo, Toyama, Wakayama, Yamanashi[Investigating][Severity: Critical][Through a supplier][Major]
Studio: website builder cloud intrusion puts company and public-sector form submissions at risk
[Web app exploit][Data leak]Leaked 21.4KOrganizations 83

		Incident	Role	Impact level				Methods	Impacts		Status
2026-10-16	2026-11-05	Studio: website builder cloud intrusion puts company and public-sector form submissions at risk	[Through a supplier]	[Major]	[Critical]	83 Digital Agency, Nagoya City, Feedforce Group Inc., Studio Inc., AISIN Corporation, Aomori Prefectural Government, Chiba Prefectural Government, Fukuoka City, Gifu Prefecture, Hiroshima Prefecture, Kanagawa Prefecture, Kyoto City, Nagano Prefectural Government, Niigata Prefecture, Okayama Prefecture, Saitama Prefecture, Aomori City, Edogawa City, Isahaya City, Koriyama City, Kusatsu City, M3, Inc., Money Forward, Inc., Nagaoka City, Nagasaki City, Niigata City, Wakayama City, Yamanashi Prefecture, Akatsuki Inc., Akatsuki Media Studio Inc., Akatsuki Solutions Inc., Akatsuki Ventures Inc., and US Inc., CrowdWorks, Inc., ExaWizards Inc., Finatext Holdings Ltd., Fuchu City (Hiroshima), Fuller, Inc., GMO Flatt Security Inc., GMO MAKESHOP Co., Ltd., GMO TECH, Inc., Hakky Inc., Hida City, Itoigawa City, JIJ Inc., jinjer Co., Ltd., Kufu Company Holdings Inc., Link-U Group Inc., Luup, Inc., Minaminihon Broadcasting Co., Ltd. (MBC), Mitsuke City, Mizkan Co., Ltd., Money Forward Home, Inc., Money Forward Kessai, Inc., Money Forward X, Inc., Monicle Financial Inc., Monicle Research Inc., OMRON Corporation, RAKSUL Inc., ReFact Inc., Relic Inc., RIZAP Group, Inc., The Ryukyu Shimpo, Sakaide City, Shima City, SmartHR, Inc., StoryHub Inc., Susaki City, Tamura City, ThinQ Healthcare Inc., Toho Gas Co., Ltd., Tohoku EPCO Frontier Co., Inc., Tokyu Land Corporation, Tomakomai City, TVer Inc., Yuzawa Town, Zenmetry Corporation, RIZAP Co., Ltd., Kenkou Medical Service Co., Ltd., RIZAP Agency Co., Ltd., RIZAP Business Solutions, Inc., RIZAP Construction Co., Ltd., RIZAP English Co., Ltd.	Aichi, Aomori, Chiba, Fukuoka, Fukushima, Gifu, Hiroshima, Hokkaido, Kagawa, Kagoshima, Kanagawa, Kochi, Kyoto, Mie, Miyagi, Nagano, Nagasaki, Niigata, Okayama, Okinawa, Saitama, Shiga, Tokyo, Toyama, Wakayama, Yamanashi	[Web app exploit]	[Data leak]	21,368	[Investigating]