Monero suffers 18-block reorg, wiping 36 minutes of transactions
Monero’s chain reorganized by 18 blocks, voiding roughly 36 minutes of activity and about 117 transactions. Community devs flagged a likely move to temporarily rolling DNS checkpoints as pools review practices after a hidden chain overtook the main network.
Monero experienced its largest rollback to date: an 18‑block reorg that erased about 36 minutes of transaction history and ~117 transfers. The event occurred around block height 3,499,659, when a previously hidden chain overtook the main network, according to community monitors.
Independent researchers linked the episode to mining pool Qubic, describing behavior consistent with selfish mining – withholding newly found blocks, then releasing a longer private chain that the network accepts as canonical under Proof‑of‑Work rules.
According to Monero Research Lab contributors, the reorg exceeded the protocol’s 10‑block lock that normally protects recent transactions, leaving some confirmations insufficient.
“Re‑orgs in excess of 9 blocks are unacceptable… It is highly likely that temporary rolling DNS checkpoints will be deployed very soon,” wrote researcher Rucknium.
Community commentator Xenu called it the largest reorg in Monero’s history, adding that the old rule‑of‑thumb about ten confirmations providing finality was broken in this case.
When the withheld chain was published and proved longer, nodes automatically switched to it and discarded the prior 18 blocks – including transactions other miners had already confirmed. Several services have since raised required confirmations for XMR deposits to mitigate near‑term risk.
Last month, Qubic was accused by community members of briefly reaching majority control while “experimenting” with the network’s defenses. In Monero’s PoW design, the longest valid chain wins; concentrated hashrate can heighten reorg risk even without a sustained 51% attack.
Despite the incident, XMR traded higher on the day and over the week, according to market trackers cited by community posts.
Project maintainers have signaled a push for temporary rolling DNS checkpoints to harden finality while broader fixes are discussed. Pool operators are under pressure to distribute hashrate and avoid practices that enable deep reorgs. Further technical notes are being collected in the project’s public issue tracker.
Recommended