Qubic, a Layer-1 blockchain designed to implement Proof of Work (PoW) to complete useful tasks, applied its mining pool to mining Monero in an attempted 51% attack against the protocol. In August 2025, the attack allegedly succeeded, with the mining pool performing a six-block deep reorganization of the Monero ledger and orphaning around 60 blocks. The 51% attack is the original threat to blockchain security, made possible by the fact that blockchain consensus algorithms essentially implement majority rule. If an attacker controls over 50% of the hashrate of a PoW blockchain, they can create new blocks faster than ... (full story)