Monero in Danger: 51% Attack Threat From Competitor Blockchain

A 51% attack happens when one group controls over half of a blockchain’s mining power, letting them cheat the system, like spending the same coins twice or blocking transactions. It’s a big threat because it completely breaks the trust in the network.

Qubic seeks to prove a point

The attack isn’t coming from a rogue hacker or state-backed actor, but from the Qubic platform, a newer layer-one project helmed by Sergey Ivancheglo, also known as CFB, a co-founder of IOTA. Qubic has made no secret of its intentions: starting August 2, it will attempt to control over half of Monero’s mining power to “demonstrate” its new consensus mechanism, Useful Proof of Work (uPoW).

Qubic’s architecture allows its AI-based miners to secure its own blockchain while simultaneously mining Monero. The profits from Monero mining are then recycled into QUBIC token burns, a mechanism meant to create a self-reinforcing deflationary loop.

Supporters frame the upcoming operation not as an attack, but as a showcase. CFB claimed:

The Monero community is divided

Qubic is now approaching 45% of Monero’s hashrate, uncomfortably close to the 51% mark that would allow it to censor transactions, perform double spends, or destabilize block consensus.

Some users on r/monero are calling this a “spoofed takeover,” alleging that Qubic inflates its hashrate metrics to create psychological pressure. Others fear more concrete consequences, with calls to action ranging from pool migration to emergency protocol adjustments.

Stress test or sabotage?

The last time Monero faced a mining centralization crisis, when MineXMR controlled over 40% in 2022, community coordination successfully defused the risk. Whether that strategy can work again is uncertain.

Some argue that Qubic is exposing fundamental flaws in Proof-of-Work networks. Others suggest the real test will be how Monero responds. For now, Qubic has not breached the 51% threshold. But with a self-imposed August 2 deadline fast approaching, the clock is ticking.