Monero, Qubic and the “51% attack”: what is the opportunity?

16/09/2025

In recent days, the cryptocurrency community was surprised by one of the largest block reorganizations ever recorded on the Monero (XMR) network. The Qubic mining pool claimed to have captured more than 51% of the blockchain's hashrate, paving the way for profound reorganizations and fueling fears of a classic 51% attack.
Despite the initial shock, the market reacted counterintuitively: the price of XMR did not fall—on the contrary, it rose more than 7% in just a few days, while trading volume nearly doubled.

The Monero blockchain underwent a reorganization of 18 blocks, erasing 118 already confirmed transactions.
This was possible because Qubic concentrated a large portion of the computing power, allowing it to "rewrite" part of the network's recent history.
Exchanges even increased deposit confirmations or temporarily suspended XMR transactions as a precaution.
At first glance, this seems like a significant risk—after all, if one entity controls more than half the hashrate, it could censor transactions or validate blocks maliciously.

The reaction was swift:
Nodes and developers monitored the event, confirming that the network remained functional and that there was no permanent loss of funds.
Exchanges adjusted confirmation policies, reducing exposure to reorganizations.
The community began discussions on official forums and in the Monero Research Lab about additional protective measures, such as checkpoints, detective mining (monitoring suspicious pool behavior), merge mining with other networks, and even deeper protocol changes (hard forks).

There is no confirmed fork yet, but some ideas are on the table:
Checkpoints/DNS checkpoints to limit deep reorganizations.
Finalization layers similar to Dash's ChainLocks, which lock blocks as soon as they are accepted.
Merge mining with other blockchains to diversify and strengthen security.
A possible adjustment to the consensus algorithm, although this would be the most drastic and complex solution.
All of these proposals have pros and cons, and the community openly discusses how to balance security and decentralization without compromising the privacy principles that make Monero unique.

The attack served as a "stress test" for the network. Despite the risk, Monero continued operating, and the practical impact was limited. This demonstrates its robustness.
The episode brought Monero back to the center of discussions in the crypto market, attracting traders, researchers, and even new supporters concerned about digital security and privacy.
Major changes to the blockchain usually only occur after extreme events. This case could accelerate structural innovations that will make the network even more resilient in the future.
For many, the narrative is not one of fragility, but of resilience: even in the face of such a serious attack, the network did not collapse, and the market responded positively.
The Qubic episode shows that Monero is not immune to risks, but also highlights the strength of its community and the market's interest in its future. Whether with minor adjustments or a possible fork, the network is likely to emerge more secure and mature.
Rather than a sign of weakness, the attack may have been the trigger for a new cycle of strengthening—and the market seems to be pricing this in.