Harmony announced Monday that its validator set will revert the layer-1 chain to blocks recorded at 11:25 pm UTC on Aug. 11, erasing more than two weeks of confirmed activity after an exploit allowed unauthorized ONE tokens to be minted and distributed across the network. The rollback covers 109,126 regular transactions and 315 staking transactions confirmed after that checkpoint.
New blocks will be produced from the next block heights using replacement databases, meaning the canonical chain will resume from the Aug. 11 state as if the intervening activity never occurred. Harmony said selective transaction restoration—cherry-picking valid activity from the discarded window and replaying it on the new chain—was not viable because account balances, contract states, nonces and other on-chain conditions would differ between the two chains, making selective restoration an inconsistent-state risk.
Investigators working with Harmony have traced nearly all of the forged ONE to specific wallets or service boundaries. The network said it is coordinating with exchanges, bridges and law enforcement to contain and recover the unauthorized supply. Harmony has not disclosed how much forged ONE reached exchanges before the exploit was contained.
ONE carried a market cap of roughly $10.8 million at last check, per CoinGecko data. Any forged supply capable of flooding a $10.8 million market cap asset could be significant relative to legitimate circulating supply, though Harmony has not published the exact volume of unauthorized tokens minted.
The decision places Harmony alongside Ravencoin in the narrow category of proof-of-stake and proof-of-work networks that have sought to reverse already-confirmed blockchain activity following an exploit. Ravencoin is managing a separate rollback dispute after a consensus flaw was exploited on its chain. Mining pools controlling the majority of Ravencoin's hash rate began building a competing chain that would reverse previously confirmed transactions, a process known as a blockchain reorganization, or reorg. Ravencoin's market cap sits at $46.3 million, with the token trading at $0.002819.
The core tension in both situations is immutability. Public blockchains derive security guarantees from the principle that confirmed transactions are final. A reorg or coordinated rollback breaks that guarantee for every address that sent or received funds inside the discarded window—not just the exploiter. For Harmony, that window contains more than 109,000 regular transactions from users who had no connection to the exploit.
Harmony's stated reason for ruling out selective restoration is technically grounded. Smart contract state on an EVM-compatible chain is not a simple ledger of debits and credits; it is a Merkle-tree state machine where every storage slot, nonce and balance feeds into the next execution. Replaying a subset of transactions from one chain state onto a different root produces indeterminate outcomes—contracts may behave differently, reverts that succeeded on the original chain may fail, and token balances derived from contract interactions cannot be safely assumed to match. Harmony's position is that a clean cut is safer than a partial replay.
The rollback announcement follows an earlier period last week when Harmony said it was considering the option after initial reports that unauthorized ONE had been minted and sent to exchanges. Monday's statement confirmed the decision and provided the specific checkpoint timestamp and transaction counts for the first time.
The discarded window spans more than 141,000 consecutive blocks, according to corroborating coverage. That block count reflects the roughly six-day gap between the Aug. 11 checkpoint and the Aug. 17 announcement, consistent with Harmony's average block time.
For protocols that hold assets bridged to or from Harmony, the replacement chain creates a state discontinuity. Bridge contracts that locked assets and issued wrapped tokens during the discarded window will need to reconcile their state against the rolled-back chain. Harmony said it is working with bridges as part of its containment effort, though it has not detailed the specific bridge protocols involved or the reconciliation mechanism.
Ravencoin's situation differs structurally. Ravencoin uses proof-of-work, meaning a reorg requires a majority of mining pools to redirect hash rate to the competing chain rather than a validator vote. The fact that pools controlling most of Ravencoin's hash rate are already building the competing chain makes the reorg likely to succeed technically, but the process is contested rather than coordinated, unlike Harmony's validator-driven decision.
