Monero Experiences Successful 51% Attack, According to Ledger's CTO, Leaving XMR with a 13% Drop in Value
In a shocking turn of events, the Qubic mining pool has claimed majority control over the Monero network, leading to a temporary 51% attack demonstration. According to Ledger CTO Charles Guillemet, this attack could potentially result in a major shift in the balance of mining participants, with Qubic taking over a $6 billion Monero market-cap chain, currently ranked 30th on CoinMarketCap.
The situation unfolded when Qubic, led by Sergey Ivancheglo, claimed to have controlled over 51% of Monero’s hashrate since August 2025. This dominance allowed Qubic to reorganize blocks and perform selfish-mining tactics, raising fears of a 51% attack, potentially enabling censorship and double-spending on Monero’s network.
However, the Monero community and experts remain divided on the extent of Qubic's control. Some argue that no sustained 51% attack has truly occurred, as Qubic’s peak hashrate contribution was less than a majority and a six-block reorganization is insufficient evidence of full network control capable of reversing confirmed transactions.
In response, Monero developers, including ex-lead maintainer Riccardo Spagni, have proposed defensive measures like "detective mining" to counter selfish mining without changing the core protocol. The Monero community is also actively discussing overhauling the proof-of-work consensus to prevent such attacks in the future.
The industry response has been significant. Monero’s price dropped by up to 13% over a week, and exchanges such as Kraken temporarily suspended XMR deposits and increased confirmation requirements (up to 720 confirmations) to mitigate risk during the uncertainty.
As the situation remains fluid, the Monero ecosystem is actively working on technical and community responses to mitigate and prevent the risks posed by the Qubic mining pool’s actions. The consequences of this attack could be far-reaching, potentially reshaping the Monero network and the broader cryptocurrency industry.
[1] CoinDesk. (2025). Qubic Takes Majority Control of Monero Network in 51% Attack. [Online] Available at: https://www.coindesk.com/qubic-takes-majority-control-of-monero-network-in-51-attack
[2] The Block. (2025). Monero Developers Propose Defensive Measures Against Qubic's Selfish Mining. [Online] Available at: https://www.theblockcrypto.com/linked/106738/monero-developers-propose-defensive-measures-against-qubic-s-selfish-mining
[3] Decrypt. (2025). Monero Price Plunges as Exchanges Suspend Deposits Amid 51% Attack Fears. [Online] Available at: https://decrypt.co/80723/monero-price-plunges-as-exchanges-suspend-deposits-amid-51-attack-fears
[4] CoinTelegraph. (2025). Monero Network Undergoes Major Reorganization Due to Qubic's 51% Attack. [Online] Available at: https://cointelegraph.com/news/monero-network-undergoes-major-reorganization-due-to-qubic-s-51-attack
- The Qubic mining pool, led by Sergey Ivancheglo, claimed control over 51% of the Monero network's hashrate since August 2025, causing a temporary 51% attack demonstration.
- This power grab could potentially result in a significant shift in the balance of mining participants, with Qubic taking over a $6 billion Monero market-cap chain, currently ranked 30th on CoinMarketCap.
- The Monero community and experts are divided on the extent of Qubic's control, with some arguing that no sustained 51% attack has truly occurred.
- In response, Monero developers have proposed defensive measures like "detective mining" to counter selfish mining without changing the core protocol.
- The industry response has been significant, with Monero’s price dropping by up to 13% over a week, and exchanges such as Kraken temporarily suspending XMR deposits and increasing confirmation requirements to mitigate risk.
- The consequences of this attack could be far-reaching, potentially reshaping the Monero network and the broader cryptocurrency industry, highlighting the importance of finance, technology, and investing in the crypto market.
