Bithumb Discloses Data Leak After Breach of Internal Mobile System

Bithumb, one of South Korea's largest cryptocurrency exchanges, has disclosed a data leak following an external hacking attack on its internal mobile groupware system, the company confirmed. The breach was discovered around October 27, 2026, and reported to South Korean authorities the same day.

The compromised system is a proprietary in-house mobile platform used by employees for internal communication, work coordination, and information sharing. Bithumb said an unauthorized external party gained abnormal access to the system, resulting in the exposure of personal information.

The exchange moved quickly to notify the Korea Internet and Security Agency, known as KISA, as well as the Personal Information Protection Commission. Both agencies are involved in overseeing cybersecurity incidents and data privacy compliance in South Korea.

Bithumb stated that it was still analyzing the full extent of the breach, including whether any customer member data was caught up in the incident. The company said in a statement: "We are analyzing the exact scope, including the possibility of member information being involved."

Critically, the exchange sought to reassure users that funds held on the platform were not in danger. "The internal work system is separated from the virtual asset trading system, so customer virtual assets cannot be accessed through this breach," Bithumb said, drawing a clear distinction between its employee-facing infrastructure and its core trading platform.

The disclosure did not arrive in isolation. Two other major South Korean financial firms — Mirae Asset and Daishin Securities — reported separate data intrusions on the same day, according to The Korea Times. The simultaneous nature of the incidents points to coordinated or at least concurrent threat activity targeting the country's financial sector.

The attack on Bithumb fits within a broader pattern of escalating cyber threats against South Korean finance. As of October 14, 2026, approximately 16 financial institutions in the country had been targeted in a wave of hacking campaigns, resulting in an estimated 100,000 instances of personal data exposure, according to Korean financial media.

Security analysts have attributed the intensifying frequency of such attacks in part to the growing use of artificial intelligence-assisted hacking tools, which are lowering the barrier to conducting sophisticated intrusions against enterprise systems. The Financial News cited the trend in commentary published the same week as the Bithumb disclosure.

Bithumb has faced security incidents before. A high-profile hack in 2017 resulted in the theft of billions of won worth of cryptocurrency, drawing international scrutiny and prompting years of investment in its trading infrastructure security. The latest breach, affecting only an internal employee system, represents a different attack surface but nonetheless raises questions about the security of internal corporate tooling at major exchanges.

The exchange said it would provide an official follow-up announcement once its investigation into the scope of the leak had been completed. Regulatory proceedings under South Korea's Personal Information Protection Act are expected to follow as KISA and the commission assess compliance and the adequacy of the company's response.