Kraken Suspends Monero Deposits Amid 51% Attack by Qubic Mining Pool

Kraken suspended Monero (XMR) deposits on August 12, 2025, following a reported 51% attack on the network. The exchange cited security concerns after detecting that a single mining pool, Qubic, had briefly gained control of more than half of the network’s total hashing power [2]. While trading and withdrawals remained unaffected, the move underscored the vulnerability of smaller blockchains to such attacks and highlighted the proactive measures exchanges take to protect users during periods of instability.

The attack involved a blockchain reorganization of up to six blocks, according to some reports, with Qubic reportedly peaking at 2.6GH/s on Monero’s network [4]. This brief but significant concentration of hashing power allowed the mining pool to execute what some experts define as a successful 51% attack. The pool’s share of the network has since declined to 35%, as noted by MiningPoolStats [1]. While Qubic claimed the event demonstrated full control over the network, Monero developers have questioned whether the attack was as impactful as claimed [3].

Monero, a privacy-focused cryptocurrency launched in 2014, is designed to obscure transaction details, including sender, receiver, and amount. This feature makes it a preferred asset among privacy advocates but also exposes the network to greater risks due to its relatively small hashrate and limited mining activity. The recent incident has reignited discussions around the trade-off between privacy and decentralization, with many in the crypto space debating whether the measures taken by Kraken are justified [1].

The attack has already raised concerns about potential financial exploitation. Some analysts suggest the attack could yield up to $100,000 in gains per day, depending on the scale and execution of double-spending or other malicious activities [5]. This economic incentive adds urgency to the need for stronger network defenses, particularly for mid-sized blockchains that struggle to attract consistent hashing power from a diverse set of participants.

The broader crypto community is now closely monitoring how Monero’s developers and community will respond to the incident. With Kraken and other exchanges taking defensive actions, the event highlights the ongoing challenges faced by privacy-focused coins in maintaining both security and decentralization. The outcome of this situation could influence future decisions regarding the adoption and governance of similar blockchains. As the network continues to stabilize, market confidence will remain a key factor in determining the long-term impact of the attack.

Source:

[1] Bitcoin - https://en.bitcoinsistemi.com/new-developments-in-altcoin-hit-by-51-attack-one-exchange-suspends-deposits/

[2] CryptoDnes.bg - https://cryptodnes.bg/en/kraken-suspends-monero-deposits-after-51-attack-linked-to-qubic-pool/

[3] Cryptonews - https://cryptonews.com/news/kraken-halts-monero-deposits-amid-51-attack-on-blockchain/

[4] BeInCrypto - https://beincrypto.com/kraken-freezes-monero-deposits-while-traders-drive-price-higher/

[5] CryptoRank - https://cryptorank.io/news/feed/1b262-6b-privacy-coin-monero-was-just-hijacked-for-100k-day-heres-why-thats-terrifying