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Nikkei Inc. Slack data leak exposing 17,368 users' names, email addresses, and chat histories

Data Leak
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Happening score
H score 19
2 unique sources, 2 articles

Summary

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Nikkei Inc. disclosed a Slack data leak affecting 17,368 registered users, exposing names, email addresses, and chat histories. The leak followed an unauthorized external login to the company’s Slack workspace after credentials were stolen from an employee's infected computer. The exposure matters because it may reveal sensitive internal communications for employees and business partners, and the incident was identified in September.

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Nikkei Inc. hit by network compromise

Incident
First: 06.11.2025 00:16 Last: 06.11.2025 00:16 Sources 1

How related: Japanese publishing giant Nikkei announced earlier today that its Slack messaging platform had been compromised, exposing the personal information of over 17,000 employees and business partners.

About this happening: **Nikkei Inc.** disclosed a **Slack account compromise** that exposed internal chat histories and account data for **17,368** registered users. The intrusion followed the theft of...

Open Happening

Timeline

  1. 06.11.2025 00:16 3 articles · 6mo ago

    Nikkei discloses Slack data exposure affecting 17,368 accounts

    Initial Disclosure

    Nikkei Inc. disclosed an unauthorized external login to its Slack workspace after an employee's personal computer was infected with a virus and Slack authentication credentials leaked. The company said names, email addresses, and chat histories for 17,368 individuals registered on Slack were potentially exposed, that employees' and business partners' data may have been affected, that no leakage of journalist source information or reporting activities had been confirmed, and that it voluntarily reported the incident to the Personal Information Protection Commission.

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