- Monero surged 5% despite suffering its largest-ever blockchain reorg, which reversed 117 transactions in an attack by Qubic, a mining pool that controls over 51% of the network’s hashrate.
- The incident has reignited debates about Monero’s decentralization and long-term security, even as XMR shows resilience in price performance.
Monero (XMR), the leading privacy-focused cryptocurrency, defied network security concerns over the weekend as its price climbed more than 5% despite suffering another major blockchain reorganization (reorg). The incident, which reversed 117 transactions, marked the largest reorg in Monero’s history and renewed debate over the project’s decentralization and resilience.
The attack was carried out by Qubic, a layer-1 AI-driven blockchain and mining pool that has increasingly dominated Monero’s hashrate.
Qubic previously executed a six-block reorg last month after amassing more than 51% of Monero’s mining power, effectively giving it the ability to alter block production. This time, the reorg began at block 3,499,659 at 5:12 a.m. UTC on Sunday and ended 43 minutes later at block 3,499,676.
Despite the disruption, Monero’s token price barely moved during the reorg. According to CoinGecko data, XMR traded flat through the attack before rallying more than 7.4% later in the day, jumping from $287.54 to $308.55.
Nothing to see here. Qubic just pulled a casual 18 blocks reorg on Monero 🤷 pic.twitter.com/fwSFY3olNu
— zuqka ×± (@AvdiuSazan) September 14, 2025
This surge came even as the broader crypto market dipped 1% over the same period. Analysts suggest that Qubic’s motives may have included attempts to prevent XMR from bleeding further in price amid ongoing pressure.
Still, the repeated reorgs have sparked alarm within the Monero community. Cryptocurrency researcher Rucknium confirmed the reorg on GitHub and warned that the network may need to consider short-term fixes such as Domain Name System (DNS) checkpoints, which allow nodes to fetch block data from trusted community servers. While this could help prevent future reorganizations, critics argue it comes at the cost of Monero’s decentralization.
Some community voices have grown more skeptical of Monero’s reliability.
Personally, I don’t consider the Monero network reliable at this point. I’ll stop accepting XMR for payments until this situation is resolved, said crypto pundit Vini Barbosa on X.
Others, like SlowMist founder Yu Xian, cautioned that unless Monero addresses block reorgs head-on, the network will remain under constant threat from entities like Qubic.
Monero developers have previously considered measures to mitigate 51% attacks, including changes to its proof-of-work algorithm, merge mining with Bitcoin, and even adopting mechanisms like Dash’s ChainLocks.
However, none of these solutions have been implemented, leaving the network exposed to powerful mining entities. Notably, Monero’s 10-block lock mechanism, which was designed to protect against smaller reorgs, was bypassed by Qubic’s latest 18-block takeover.
Even so, XMR has shown resilience in the face of adversity. Since Qubic’s influence became widely known in late July, the token has only declined by about 5.8%. Its ability to rebound in price, even during moments of technical vulnerability, highlights both the loyalty of its community and the ongoing demand for private, censorship-resistant money.
Whether Monero can resolve its centralization risks without sacrificing its privacy ethos remains uncertain. But for now, investors appear willing to look past the turbulence—at least as long as XMR continues to hold its ground.
