Overview

• An 18-block rollback between heights 3,499,659 and 3,499,676 erased roughly 36 minutes of chain history and invalidated about 117–118 transactions.
• Observers attributed the event to Qubic briefly controlling over 51% of network hashrate and releasing a longer hidden chain, consistent with withheld mining behavior.
• Some outlets reported no confirmed double-spends, though accounts differ on whether any reversals amounted to a successful spend conflict.
• XMR jumped to roughly $308–$330 before settling near $300–$310, with spot volumes up about 25% and derivatives activity and open interest rising.
• The episode renewed debate over security measures such as merge-mining, localized hardware, or ChainLocks-style protections, following a smaller six-block reorg linked to Qubic in August.