Mercado Bitcoin suspends deposits and withdrawals after reported security incident

Mercado Bitcoin suspended deposits and withdrawals on November 2, 2026, after identifying what it described as a security incident in one of its systems.

The Brazilian exchange said customers were not harmed and that no data breach occurred. It has not publicly identified the affected system or explained how an attacker may have obtained signing access.

Independent blockchain investigations, however, estimated that more than $40 million in assets moved from wallets linked to Mercado Bitcoin across at least 10 blockchains. The amount remains unconfirmed by the exchange, and reported estimates differ.

Investigators report transfers across 10 blockchains

Security firms tracking the activity said exchange-linked wallets saw transfers exceeding $40 million across at least 10 blockchains. Bitquery placed its estimate at $48.5 million, while another reported estimate was about $46 million.

These figures are third-party blockchain analyses rather than an amount confirmed by Mercado Bitcoin. The available evidence does not establish the final loss or whether all transferred assets were controlled in the same way.

• Reported estimates exceed $40 million.
• Bitquery estimated $48.5 million moved across 10 blockchains.
• Mercado Bitcoin has not confirmed a loss amount.

Customer impact remains disputed

Mercado Bitcoin said there was no harm to customers and no data breach. Bitquery separately reported that thousands of customer deposit addresses were subsequently emptied.

Those statements leave key questions unresolved, including the financial impact of the incident and any customer exposure. The exchange has not publicly disclosed the compromised system or the method used to obtain signing access.

The case adds to recent security-focused developments in the sector, including the Coinbase report that an Amplitude incident exposed some customer contact information.

What is known and what remains undisclosed

The confirmed operational response is the suspension of deposits and withdrawals following the reported security incident. The exchange characterized the event as a security incident, rather than publicly identifying it as a hack.

Blockchain investigators have provided estimates of asset movements, but their findings do not resolve the cause of the incident. Further clarity depends on additional disclosures from Mercado Bitcoin or independently verifiable technical evidence.

The episode also illustrates why custody infrastructure and wallet-signing controls remain central concerns for exchanges, alongside software-security issues such as the vulnerability addressed by Electrum for malicious-server payment diversion.

• Deposits and withdrawals were suspended on November 2, 2026.
• Mercado Bitcoin said no customer harm or data breach occurred.
• The affected system and attack method have not been publicly disclosed.

Continue reading: Coinbase report that an Amplitude incident exposed some customer contact information on BTCNews.

Continue reading: vulnerability addressed by Electrum for malicious-server payment diversion on BTCNews.

Sources

• CoinDesk: Brazil’s Mercado Bitcoin halts withdrawals after $40 million drained across 10 chains
• Bitquery: Mercado Bitcoin Hack: $48.5M Taken on 10 Blockchains
• The Block: Mercado Bitcoin, Brazil’s largest crypto exchange, hit by $46 million security breach
• Portal do Bitcoin: Mercado Bitcoin Suffers Hack but Says Customer Funds Are Safe

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