South Korean cryptocurrency exchange Bithumb is investigating whether customer information was exposed after an unauthorized party accessed its internal mobile groupware system. The incident was one of three data breaches reported by financial firms in the country on Wednesday, raising fresh concerns about the security of customer information across both digital-asset and traditional financial businesses.
Bithumb investigates possible customer-data leak
Bithumb, South Korea’s second-largest crypto exchange, said an outside party gained access to its internal mobile groupware system. The exchange confirmed that personal information was leaked, but it has not established publicly whether customer data was included in the exposed material.
According to Decrypt, the company is investigating the scope of the incident. An industry source cited by Yonhap News Agency said that some personal information belonging to Bithumb customers had been leaked. Bithumb has not disclosed how the intruder entered the system, and the exchange has not provided a figure for the number of people potentially affected.
The distinction between an internal-system breach and a direct theft of cryptocurrency is important. The information currently described as exposed is personal data, while there has been no statement in the source material that customer funds were taken. The investigation is intended to determine what information was accessed and whether it included data held for exchange users.
Two other South Korean firms report breaches
Bithumb was among three South Korean financial companies that reported security incidents on the same day. Daishin Securities, a brokerage, said it detected signs of unauthorized access the previous week and found that information belonging to 38,490 customers had been leaked.
The data identified by Daishin included customers’ names, email addresses and mobile phone numbers. The brokerage said it would compensate customers for any damage resulting from the incident in accordance with the law.
Mirae Asset Global Investments, an asset manager, also confirmed that it had experienced a hacking incident. South Korean financial authorities have begun inspecting the three cases. Representatives of the companies could not be immediately reached for comment by Reuters, which reported the developments while citing Yonhap for details about the incidents.
The cases come after a broader series of attacks on South Korean financial companies. The Financial Services Commission said earlier in October that 16 firms, including banks, had suffered attacks that resulted in approximately 100,000 data leaks. That wider pattern has placed additional attention on how financial institutions protect personal information and respond when unauthorized access is detected.
Why leaked contact data matters
Personal details such as email addresses and phone numbers can be used in phishing attempts, fraudulent messages and social-engineering schemes. Changpeng “CZ” Zhao, founder of Binance, referred to the South Korean incidents in a post on Wednesday alongside a separate security event involving Coinbase’s analytics vendor, Amplitude.
Coinbase said the Amplitude incident exposed some customers’ contact data, according to the source material. Zhao said leaked exchange information is often used for phishing, SIM swapping and social engineering, and warned that exposed addresses and holdings data had contributed to real-world extortion and robberies. He urged users to use a distinct email alias for each exchange, avoid text-message-based two-factor authentication and ask their mobile carrier for a number lock.
Separately, South Korea’s Science Ministry and the Korea Internet & Security Agency urged website operators to check for recently disclosed vulnerabilities in PHP, a programming language widely used across the web. The flaws can allow attackers to run commands on a server without logging in. Bithumb has not said that these vulnerabilities were involved in its breach, and the source material does not establish how the exchange’s system was accessed.
Bithumb’s difficult 2026
The security incident adds to a turbulent year for Bithumb. In February, the exchange mistakenly credited 695 users with a combined 620,000 BTC during a promotion intended to distribute small cash rewards. The Bitcoin existed only on Bithumb’s internal ledger, and the company said it recovered 99.7% of it. The incorrectly credited amount was valued at about $43 billion at the time.
In March, South Korea’s Financial Intelligence Unit fined Bithumb 36.8 billion won, or $24.6 million, and ordered a six-month partial suspension over anti-money-laundering failures. A Seoul court blocked that suspension in April.
Bithumb has subsequently outlined a three-stage plan to seek a stock-market listing in 2028. Its chief executive, Lee Jae-won, was also booked in June as a bribery suspect in a case involving the alleged hiring of a National Assembly member’s son. The source material does not indicate that those earlier matters are connected to the newly reported data breach.
Moneyiar market picture
Moneyiar data as of October 25, 2026, shows Ethereum at $2,342.0570017305, up 0.02% over 24 hours but down 1.77% over seven days. Data Network stood at $0.1503553856, down 4.42% in 24 hours and 7.71% over seven days.
Alchemy Pay was priced at $0.0050519273, with a 24-hour decline of 2.05% and a seven-day decline of 2.83%. Ore traded at $164.7502665491, up 4.48% over 24 hours and 56.42% over seven days. These figures are Moneyiar market data recorded at approximately 10:38-10:39 p.m. Iran time on October 25, 2026, and are separate from the Bithumb security investigation.
