Monero appears to be in the midst of a successful 51% attack

What Was Alleged to Happen

• A group associated with Qubic claimed to control >50% of Monero’s hashrate, enabling chain reorganizations, censorship, and theoretical double-spends.
• Some users observed unusual reorg activity on their nodes, consistent with elevated hash concentration.

Was It Really a 51% Attack?

• Several commenters argue this was not a sustained, classical 51% attack: reported reorg depth (~6 blocks) is far below the 10-block confirmation window Monero uses.
• Public pool stats didn’t clearly show a single entity above 50%; much of the power was hidden as “unknown,” and Qubic allegedly disabled hashrate reporting, making verification unclear.
• Others suspect exaggeration or marketing: Qubic is called an “unreliable narrator” and its “planned stress test” framing is viewed as unverifiable.

What a 51% Attack Can and Can’t Do

• Consensus: majority hash allows:
  • Rewriting recent history (reorgs), double-spending attacker’s own coins, and censoring transactions.
  • Potentially capturing all block rewards via selfish mining.
• It does not allow:
  • Signing transactions without private keys, directly stealing random users’ coins, or breaking Monero’s anonymity.

Economic Motives and Costs

• Some claim such attacks are “expensive”; others note they can be profitable if hashpower is acquired at normal mining margins or combined with shorting the coin.
• Qubic reportedly subsidized miners (e.g., paying extra in its own token) to redirect CPU power to Monero, possibly profiting from publicity and token demand rather than on-chain theft.
• Debate over whether a successful visible attack would crash XMR and undermine any on-chain profit, but could still be worthwhile for someone betting against Monero or seeking to destroy trust.

Monero’s Design and Possible Mitigations

• Monero’s CPU-oriented RandomX is defended as ASIC-resistant but criticized as making rental/redirected CPU attacks easier.
• Proposed defenses include PoS or hybrid PoW+PoS, ASIC-based PoW, or BFT layers; whitelisting miners is rejected as centralizing.

Views on Qubic and “Proof of Useful Work”

• Qubic’s “decentralized AI” and “useful PoW” marketing is widely mocked; some call it ponzi-like or centralized compute wrapped in crypto rhetoric.
• More rigorous “proof of useful work” research is mentioned, but several argue that if the work has independent value, it weakens PoW’s security assumptions.

Broader Trust & Political Angle

• Some see this as another in a long line of pressures against Monero (delistings, reputational attacks), speculate about state-level hostility to strong financial privacy, and question how users should react if ledger trust is repeatedly challenged.