South Korean crypto exchange Bithumb reported a breach of its internal corporate system, resulting in a leak of personal data. American exchange Coinbase confirmed that due to an incident at its analytics contractor Amplitude, information of some of its clients was exposed.
According to statements from both companies, user funds were not affected. As of writing, no connection between the attacks has been established.
Bithumb’s Internal System Breach
Bithumb detected unauthorized access to its corporate mobile system on October 27. The exchange notified regulators — KISA and PIPC — the same day.
The incident affected DaouOffice, a collaboration platform by Daou Technology used by exchange employees for messaging and file sharing.
According to Money Today , hackers allegedly stole names, departmental information, and contacts of Bithumb employees. The company is currently checking whether client data, shared by employees in work correspondence, was also compromised.
“Although only employees use the messenger, files exchanged may have contained client information, so we are conducting additional checks,” a Bithumb representative explained .
“Although only employees use the messenger, files exchanged may have contained client information, so we are conducting additional checks,” a Bithumb representative explained .
He emphasized that the corporate system is physically isolated from the trading infrastructure, preventing access to client funds. No cryptocurrency thefts have been reported.
Bithumb has not yet disclosed the number of affected individuals, the full list of compromised data, or the method of intrusion.
The breach occurred amid a series of cyberattacks on South Korean financial institutions . On October 28, broker Daishin Securities and asset manager Mirae Asset Global Investments also reported data breaches.
Daishin confirmed the compromise of information for 38,490 clients, including names, contacts, and addresses. Mirae Asset stated it blocked abnormal access to parts of its web systems, and investor data was not affected.
Coinbase Reports Contractor Data Leak
Coinbase denied reports of a breach in its systems. According to the exchange, the leak occurred at Amplitude, a third-party analytics provider serving the trading platform and other companies.
Support clarified that data of a small portion of users was exposed. Information of other Amplitude clients was also affected.
Coinbase had a data breach 😭 — zubic (@zubic_eth) October 27, 2026
Coinbase had a data breach 😭
— zubic (@zubic_eth) October 27, 2026
Coinbase did not specify the number of affected individuals or the nature of the compromised information. The exchange is notifying impacted users via email, as required by law.
Earlier this year, Bithumb mistakenly credited users with approximately 620,000 BTC during a promotional campaign. In June, PIPC ordered the exchange to pay 210 million won for transferring user data to foreign companies without consent.
Previously, in a lawsuit against TaskUs , details of a 2025 Coinbase client data leak were revealed. According to Reuters, employees of the contractor’s Indian division were allegedly selling user information to malicious actors.
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