In August 2025, AI-focused project Qubic claimed it had successfully executed a 51% attack on privacy coin Monero, asserting control over a majority of the network’s hashrate and implying it could reorganize the chain and censor or double-spend transactions. Early coverage framed this as a potentially historic takeover of a roughly $6–8 billion privacy network by a project with a self-described $300 million valuation, raising concerns about Monero’s security model and centralization risks in its CPU-focused mining. Shortly after Qubic’s announcement, on-chain analysts and community researchers began examining block production and hashrate distribution and disputed the 51% claim. A detailed review of nearly 700 blocks indicated Qubic’s effective share of Monero’s hashrate was closer to 30–35%, not a controlling majority, and the network showed no evidence of successful double-spends, persistent chain reorganizations, or transaction censorship. As scrutiny increased, Qubic’s share reportedly declined further to around 30%, and Monero’s chain continued operating normally, with no user funds lost and no lasting disruption. The episode became a case study in how exaggerated “51% attack” narratives can spread, while also highlighting ongoing concerns about hashrate concentration in single pools and the challenges of accurately measuring real-time control in privacy-oriented proof-of-work networks.

AI-generated background, compiled from web sources — not editorial content.

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