# Security incidents at Brazilian cryptocurrency exchanges

> Developing situation record from CLSTR: https://clstr.news/situations/security-incidents-at-brazilian-cryptocurrency-exchanges
> Updated: 2026-11-02T13:39:00.000Z. Sources: 44. Developments: 2.

Brazilian cryptocurrency exchanges have faced significant security and operational challenges. In October, Brasil Bitcoin investigated allegations of a massive data breach after a cybercriminal claimed to possess the personal and transaction data of approximately 657,000 investors. The company stated that its technical team was verifying the leak and noted that no customer funds were accessed. In November, Mercado Bitcoin suspended all deposits and withdrawals following a security incident. While the exchange maintained that no customer funds were harmed and no data breach occurred, security firm Hypernative reported suspicious movements totaling approximately US$ 40 million across at least ten blockchains. On November 2, Mercado Bitcoin confirmed it had contained a breach within one of its systems. The exchange stated the impact reportedly affected the company’s own resources rather than user funds. Hypernative updated its assessment, reporting suspicious movements between US$ 40 million and US$ 45 million across at least ten blockchain networks, including Bitcoin, Ethereum, Solana, and others. Specific assets involved include approximately 106 BTC, 2,852 ETH, 10,700 SOL, 6.7 million XLM, and 77,000 AVAX. Security firms including CertiK and Hypernative noted that attackers appeared to use authorized signatures rather than a smart contract exploit, suggesting potentially compromised private keys. Tether and Circle have reportedly frozen approximately US$ 6.2 million in stolen funds. Mercado Bitcoin is reportedly working with authorities and partners, such as Chainalysis and Paxos, to track assets and has published destination wallet addresses to assist investigators. Recent updates indicate that collaborative recovery efforts involving Tether, Circle, Paxos, BRL1, and Chainalysis have helped immobilize assets totaling over US$ 9 million, with Tether specifically confirming it has frozen over US$ 4.5 million in USDT tied to the incident.

## Claims

- The exchange reported that no customer funds were lost and no data breach occurred. (reported by 27 sources)
- Hypernative detected suspicious movements totaling approximately US$ 40 million. (reported by 22 sources)
- Mercado Bitcoin suspended deposits and withdrawals as a preventive measure. (reported by 29 sources)
- Mercado Bitcoin identified and contained a security incident in one of its systems on November 2. (reported by 25 sources)
- Suspicious movements involved at least ten blockchains, including Bitcoin and Ethereum. (reported by 16 sources)
- The suspicious movements included 106 BTC and 2,852 ETH. (reported by 11 sources)
- Tether froze approximately US$ 4.5 million in USDT tied to the incident. (reported by 11 sources)
- Mercado Bitcoin plans to cover the loss from its own funds. (reported by 2 sources)

## Timeline

### 2026-11-02: Mercado Bitcoin suspends operations after security breach

Brazil's Mercado Bitcoin suspended deposits and withdrawals after a security breach involving an estimated US$ 38 to US$ 49 million in digital assets across multiple blockchains.

44 sources. https://clstr.news/cluster/mercado-bitcoin-suspends-transactions-following-security-incident

### 2026-10-10: Brasil Bitcoin faces data breach allegations and corporate shifts

Brasil Bitcoin is investigating an alleged data breach affecting 657,000 users while navigating corporate shifts and new regulatory requirements from the Banco Central do Brasil.

2 sources. https://clstr.news/cluster/brasil-bitcoin-faces-data-breach-allegations-and-corporate-shifts

---
Cite as: Security incidents at Brazilian cryptocurrency exchanges. CLSTR, https://clstr.news/situations/security-incidents-at-brazilian-cryptocurrency-exchanges