Mercado Bitcoin (MB) confirmed on Monday (2) that one of its systems had suffered a security incident and temporarily suspended deposits and withdrawals. In an official statement on X, the exchange said that customers had suffered no losses and no data had been leaked.
The statement was published after blockchain security company Hypernative warned of a possible hacker attack involving losses of more than US$40 million from wallets attributed to MB.
Official statement:
We quickly identified and contained a security incident involving one of our systems early this morning.
We want to reiterate that:
• No clients suffered any losses;
• No data was leaked.
As a protective measure, deposits and withdrawals…
— Mercado Bitcoin (@MercadoBitcoin) November 2, 2026
Here is the full statement:
We quickly identified and contained a security incident in one of our systems early this morning.
We want to reiterate that:
• No clients suffered any losses;
• No data was leaked.
As a protective measure, deposits and withdrawals have been temporarily suspended. Our teams are working to investigate the incident, trace the assets, and coordinate measures with the relevant authorities.
We will post regular updates here.
The statement does not provide any figures, explain what happened, or mention Hypernative’s alert. It also gives no timeline for the resumption of deposits and withdrawals.
What Hypernative reported
According to Hypernative, the possible attack involved wallets across at least ten blockchains, including Bitcoin, Ethereum, Solana, Tron, Polygon, Arbitrum, Avalanche, BNB Smart Chain, and Stellar. The first suspicious transactions appeared at 2:15 UTC, equivalent to 11:15 p.m. on Sunday (November 1) in Brasília.
The largest transfers took place between 6:19 and 6:53 UTC, or between 3:19 and 3:53 a.m. Brasília time. During that window, wallets attributed to MB sent most of the funds to newly created addresses linked to the possible attacker. MB’s statement refers to an incident “early this morning,” the same period as these transfers, but does not directly connect it to the alert.
Rather than exploiting smart contract vulnerabilities, the transactions were ordinary cryptocurrency transfers, signed as if they had been authorized by the originating wallets themselves. Hypernative says it is still unclear how the attacker could have obtained this signing capability. Questions include whether private keys may have been exposed and whether there were flaws in the infrastructure that authorizes transactions.
The estimate of more than US$40 million is preliminary and depends on confirming that all the source addresses belong to the exchange. According to the alert, addresses linked to the possible attacker hold 2,852 ETH, 106 BTC, 10,700 SOL, 6.7 million XLM, 77,000 AVAX, 3.07 million XDC, and 1.7 million TRX, as well as more than 200 other tokens.
Hypernative shared examples of the transactions, including one on the Ethereum network and another on the Bitcoin network. A check on Beaconcha.in shows a balance of about 2,852 ETH at the cited Ethereum address, consistent with the findings. However, this balance alone does not prove that the funds came from Mercado Bitcoin. The flow of funds can be tracked on Hypernative’s platform.
What is still unknown
Questions remain about the cause of the incident, the actual value of the losses, whether the assets moved belonged to clients or the exchange itself, and when deposits and withdrawals will return to normal. MB says it is investigating the incident, tracing the assets, and working with the authorities, and promises regular updates.
The incident comes days after the US$6.3 billion hack of Binance and reignites the debate about the security of exchanges. To understand how the Brazilian platform is generally assessed, BeInCrypto has already explained whether Mercado Bitcoin is safe.
Mercado Bitcoin has just confirmed a hacker attack.
As a protective measure, deposits and withdrawals have been temporarily suspended.
— Luís De Magalhães (@LuisDeMaga) November 2, 2026
The article Mercado Bitcoin Suffers Hacker Attack and Suspends Deposits and Withdrawals was first published on BeInCrypto Brasil.