Mercado Bitcoin, Brazil’s largest cryptocurrency exchange, confirmed on November 2 that it suffered a cyberattack and has temporarily suspended deposits and withdrawals as a precaution.
The company said it detected the security incident early Monday morning and quickly contained it, assuring customers that their funds were not affected and that no personal data breach occurred. However, blockchain security firm Hypernative flagged preliminary estimates of more than $40 million in suspicious transfers across multiple blockchains.
The exchange has not disclosed which system was compromised, whether any assets were stolen, or how many accounts may have been involved. Security teams are investigating, tracking assets and coordinating with authorities. A timetable for resuming deposits and withdrawals has not been announced, and the status of other platform functions, including trading, remains unclear.
The incident comes during a turbulent security week for crypto: on October 29, Binance reported a major breach affecting about $6.3 billion in assets, leading to temporary withdrawal restrictions; Aave froze several markets after a wallet linked to the Binance attacker deposited 60 million USDT and borrowed 19,762 WETH; and BTCPay Server warned of unauthorized hot wallet withdrawals.
The Mercado Bitcoin case may intensify scrutiny of cybersecurity practices at regulated exchanges, especially as Brazilian authorities continue to shape local crypto oversight.
