Monero’s privacy chain endured its deepest-ever chain reorganization in the last 24 hours, when 18 consecutive blocks were replaced, briefly “rewriting” roughly 36 minutes of ledger history and invalidating about 118 already-confirmed transactions. Multiple independent monitors flagged the event late Sunday into Monday, describing a rollback spanning block heights 3,499,659 through 3,499,676 before nodes converged on a new best chain. With Monero targeting two-minute blocks, an 18-block reorg translates to ~36 minutes of history—an extraordinary depth for a mature proof-of-work network.
Qubic founder Sergey Ivancheglo, who is known by the alias “Come-from-Beyond”, posted via X: “Monero will stay because Qubic wanted it to stay.”
At a technical level, a chain reorg occurs when two valid histories compete and the network ultimately converges on the one with the most accumulated proof-of-work, discarding the other and any transactions exclusive to it. In Monero’s design, two-minute target block intervals and dynamic block sizing aim to keep throughput smooth while preserving privacy primitives like ring signatures and stealth addresses.
In practice, however, a miner or pool with outsized hashpower can—at least in bursts—privately extend a side chain and then release it, “out-working” the public tip and forcing nodes to reorganize. That is what appears to have happened here, with a depth that exceeded the de facto 10-confirmation comfort zone commonly used by wallets and exchanges.
Each trade-off is sharp: checkpoints and ChainLocks introduce degrees of centralization or new trust assumptions, while pool-level changes may be unevenly adopted. The community has not yet coalesced around a specific fix, but the urgency has unmistakably increased.
Markets treated the event with surprising resilience. Within hours, XMR rallied between roughly 5% and 7%, trading above $300 on some venues.
