Scott Emick
9/19/25
Summary of the RIAT Article “qubic attack on XMR monero: No 51% attack has happened” by parasew [https://riat.at/qubic-attack-on-xmr-monero-no-51-attack-proven/]
On August 21, 2025, RIAT published an analysis responding to Qubic’s widely publicized claim that it had achieved a 51% takeover of the Monero (XMR) network.
- Self-Reported Hashrate: Qubic claimed to have reached 2.6 GH/s, while the Monero network was operating at ~6.25–6.71 GH/s. This means Qubic controlled at most ~28% of the total hashrate — far below the 51% threshold.
- Media Amplification: Major crypto outlets like CoinDesk and CoinTelegraph repeated Qubic’s claim without verifying the numbers. Independent researchers (BitMEX Research, The Block, Kaspa’s Shai Wyborski, and the Monero community) quickly debunked it.
- What Actually Happened: Qubic briefly mined 6 consecutive blocks using a strategy called selfish mining. While this caused a temporary chain reorganization (reorg), it was not enough to double-spend or control the network.
- Why It Matters: Exchanges typically require 10+ confirmations before considering a transaction final. A 6-block reorg does not meet the threshold needed to reverse fully confirmed transactions.
- Possible Motive: RIAT suggested Qubic’s campaign was designed to spread FUD (fear, uncertainty, doubt) and possibly suppress Monero’s price, allowing cheap accumulation by exchanges and speculators.
- Community Takeaway: Monero remains secure, but the incident highlights the need for decentralized mining solutions like P2Pool and continued research into defenses against selfish mining.
Review and Perspective
RIAT makes a strong case that no true 51% attack occurred. The math doesn’t support Qubic’s claim, and the community quickly showed that their narrative was a PR stunt amplified by careless reporting.
At the same time, RIAT acknowledges that a 6-block reorg did occur. While not catastrophic, it shows that concentrated hashrate can still cause real disruption.
From my perspective, I don’t fully dismiss the incident. I know someone who claims their XMR transaction was actually reversed during the reorg. If true, this suggests that even without a majority attack, temporary reorganizations can affect end users in meaningful ways.
If you are receiving from an untrusted source, I recommend 20 or more confirmations which takes approximately 40 minutes to cover these possible minor reorganizations.
This raises an important point:
- RIAT is right that the network wasn’t taken over.
- But users still experienced disruption — and perception matters.
For Monero to remain resilient, it’s not just about avoiding a 51% attack. It’s also about reducing the ability of any single actor to create instability, even briefly.
Conclusion
The Qubic saga serves as both a debunking of false claims and a warning about network fragility. Monero wasn’t overtaken — but the scare reminded everyone why decentralization of mining and careful, critical reporting are essential.
Events like this are likely to push Monero developers and the community toward protocol improvements that make selfish mining less viable, further strengthening the network’s long-term security.
