Monero Faces Major Disruption as Qubic Claims Possible 51% Attack Amid Ongoing Mining War

The privacy-focused cryptocurrency Monero has been hit by significant network turbulence after 60 blocks were discarded from its blockchain within 24 hours. The disruption coincides with claims from the Qubic network that it may have successfully carried out a rare and serious 51% attack.

According to the Monero Consensus Status dashboard, the discarded blocks—known as “orphans”—represent valid blocks rejected because competing ones were accepted first. The spike in orphaned blocks appears linked to Qubic’s openly admitted practice of selfish mining, where miners strategically withhold blocks to gain an advantage, leaving honest miners’ work discarded.

xmrconsensus

How the Qubic Attack Works

Qubic miners have been redirecting computing power to mine Monero, selling the rewards to buy and burn Qubic tokens, while being paid in QUBIC cryptocurrency. This setup reportedly offers higher payouts than standard Monero mining, incentivizing participation.

Qubic founder Sergey Ivancheglo claimed in a Tuesday post on X that “Qubic has achieved 51% over Monero” and is awaiting independent confirmation. A 51% attack—when a single entity controls more than half of a blockchain’s mining power—can enable transaction manipulation, double spending, or censorship.

Zhong Chenming, co-founder of blockchain security firm SlowMist, suggested the attack “seems to have succeeded,” though he noted the costs were high and the ultimate economic gain remains unclear.

Disputed Claims and Conflicting Data

Not all experts are convinced a successful 51% attack occurred. Monero’s network hashrate is estimated at 5 GH/s, while Qubic’s reported peak of 3.01 GH/s could be enough for brief control but its current hashrate of 2.08 GH/s falls short of majority control.

Monero Hashrate Chart - XMR Hashrate

The Monero hashrate chart provides the current XMR hashrate as well as the history of Monero hashrate in graph format with an option to expand the Monero global hashrate chart time span back to 2015.

CoinWarz - Cryptocurrency Mining Profitability

Luke Parker, lead developer at SeraiDEX, cautioned that a six-block chain reorganization with orphaning “does not mean a 51% attack was successful” and may instead be the result of an adversary with high hashrate getting “lucky.”

Escalating “Hack War”

This incident is the latest in an intensifying digital conflict between the two networks. Ivancheglo has accused Monero developers of disrupting Qubic’s operations, while Monero supporters allege Qubic’s tactics amount to an economic assault on the network. The back-and-forth began in late July when the Monero community detected unusual mining incentives seemingly designed to take control of its hashrate.

Niko Demchuk, head of legal at AMLBot, said Qubic’s actions could potentially qualify as “computer sabotage” or “unauthorized access” under Belarusian and EU laws, although existing statutes do not explicitly address 51% attacks.

Price Reaction

Monero’s price has reflected market unease, falling over 8.6% in the past day from around $276 to $247. Investors and developers are watching closely as the situation evolves.