Harmony's layer-1 network plans to revert its blockchain state to a checkpoint recorded at 11:25 p.m. UTC on Aug. 11, the team announced Monday, Aug. 17, after an exploit allowed attackers to mint forged ONE tokens and route them across the network. The rollback will erase 109,126 regular transactions and 315 staking transactions confirmed after that block height.
Validators will build new blocks from that height using replacement databases rather than the existing chain state. Harmony ruled out selective restoration of transactions, saying that picking and choosing which records to keep would produce mismatched balances, broken contract states, inconsistent nonces and other state-level conflicts that would make the replacement chain unreliable.
Investigators traced nearly all of the forged ONE to specific wallets or service boundaries before the Monday announcement. The team said it is working with exchanges, bridges and law enforcement to contain the unauthorized supply. No named exchange or bridge has publicly confirmed asset freezes as of the announcement.
ONE had a market cap of roughly $10.8 million at the time of the announcement, according to CoinGecko data, reflecting how far the token has fallen from its 2021 peak. The small market cap limits the dollar-denominated damage from the forged supply but does not reduce the technical severity of a full-chain rollback on a live network.
The mechanics of the rollback are straightforward in theory but operationally heavy. Every validator must coordinate the switch to the replacement database at the same block height. Any node that continues building on the old chain after the cutover point will fork off the network permanently. Harmony has not published a validator coordination deadline or a grace period for exchanges to pause deposits and withdrawals ahead of the revert.
The 109,126 discarded regular transactions represent real user activity—transfers, contract calls and other on-chain interactions—completed in good faith between Aug. 11 and Aug. 17. Users whose transactions fall inside that window will see their chain state revert to pre-exploit conditions. Funds moved out of wallets during that period reappear; funds moved in disappear.
Harmony is not alone in pursuing a post-exploit rollback. Ravencoin faces a separate dispute after a consensus flaw was exploited, prompting mining pools controlling most of the network's hash rate to begin building a competing chain that would reverse previously confirmed transactions. That competing chain covers three days of activity and represents a contested reorganization rather than a coordinated validator rollback, making Ravencoin's situation structurally different from Harmony's. Ravencoin traded at $0.002819, giving it a market cap of $46.3 million.
Rollbacks on layer-1 networks are rare precisely because they break the property that users and applications rely on most: finality. A confirmed transaction is supposed to be irreversible. When a network reverses that guarantee—even to correct an exploit—every application built on top of the chain must account for the possibility that on-chain state is not permanent. Bridges are particularly exposed: any bridge that processed withdrawals during the discarded window and released funds on the destination chain now holds a liability the Harmony side no longer recognizes.
Harmony's history adds context. The network suffered a $100 million Horizon bridge hack in June 2022, one of the largest bridge exploits of that cycle. The team pursued recovery through token minting at the time rather than a chain rollback. The current incident is smaller by market-cap terms but has produced a more aggressive on-chain response: a full state revert rather than a supply-side patch.
The project said new blocks will be produced from the replacement databases immediately after validators complete the switch. No timeline for exchange relisting or resumption of normal deposit and withdrawal flows was included in the Monday announcement.
