The Qubic team announced that it had reached majority hashrate control, briefly reorganized blocks, and chose not to execute a full network takeover. That version of events has since been echoed across social media and crypto news outlets – but also met with strong pushback from developers, researchers, and community members.
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Qubic’s Version of Events
According to Qubic, the goal was never to attack Monero in the traditional sense, but to demonstrate the real-world capabilities of its Useful Proof of Work (uPoW) model. In their official statement, Qubic claimed that on August 11, their pool reached over 51% of Monero’s hashrate. During this period, they say they successfully executed a blockchain reorganization by mining 63 out of 122 blocks – a level of dominance that, according to them, proves control.
The demonstration, as described, was carried out through a strategy based on selfish mining. Rather than broadcasting every new block immediately, the Qubic pool withheld some of its blocks to gain a strategic edge. This allowed them to gain a larger share of rewards and exert influence over the consensus process, even in periods where their hashrate fluctuated below the 51% mark.
The Qubic team stated that they had multiple chances to escalate the demonstration into a full-scale takeover, including orphaning all other blocks on the network. However, they chose not to proceed, citing concerns about damaging Monero’s price or undermining its ecosystem.
Read also: Solana Is Built to Resist 51% Attacks – Here’s How
The Case Against
Not everyone agrees with Qubic’s interpretation. Several developers and researchers have pointed out that there is no definitive public data proving they had over 51% of the network’s hashrate. Critics argue that the pool’s hashrate never exceeded 40%, and that the reorganization could have been the result of mining luck rather than actual control.
BitMEX Research noted that while Qubic may have produced a higher-than-expected number of blocks for a short time, this doesn’t necessarily prove majority control. They emphasized that the network’s estimated hashrate was likely underreported, due to Qubic taking its mining stats offline and the use of selfish mining obscuring actual work contributed. According to their analysis, it’s more plausible that Qubic crossed the profitability threshold for selfish mining, which can be effective with as little as 33% hashrate, but fell short of true dominance.
Others have made similar arguments. Luke Parker, developer of SeraiDEX, said the six-block reorg seen on Monero’s chain is not uncommon in high-hash environments and doesn’t automatically indicate a 51% attack. In his view, the event was the result of a pool with high, but not majority, hashrate getting lucky during a short window.
Independent pool metrics from MiningPoolStats support some of the skepticism. Around the time of the event, the largest known mining pools processed less than half of the blocks, with the remainder attributed to unidentified sources. That leaves room for interpretation but doesn’t confirm Qubic’s claimed majority share.
What We Know from the Data
It is confirmed that Monero experienced a six-block reorganization, and that block production has recently been concentrated in fewer, less identifiable pools. Qubic’s own reporting shows a temporary dominance in block production, but it’s not independently verifiable whether that was backed by a sustained >51% hashrate. The team has promised third-party verification, but as of now, no independent analysis has been published.
Price Reaction
XMR dropped roughly 13% since the news began spreading, hitting a 3-month low. In contrast, QUBIC’s token saw a modest rally, likely driven by visibility around the event and ongoing miner rewards distributed through Qubic’s internal economy.
What Comes Next
Qubic has stated that this is not the end. Their goal, according to public posts, is to eventually provide Monero’s security by becoming its de facto mining base – turning what was an attack vector into a service model.
At the same time, the Monero community is discussing responses, including potential protocol adjustments and renewed calls for decentralized mining through p2pool or solo setups.
For now, there is no confirmed evidence of double-spends or censorship on Monero. But the incident has sparked new discussions about hashrate centralization, incentive-based attacks, and the practical limits of Proof of Work security.
