Concord has proposed rolling again its blockchain to 2 Aug. 11 checkpoints, a restoration plan that might discard greater than 109,000 common transactions because the community removes ONE created by a solid mint.
In accordance with Concord’s newest incident replace on X, validators would retain shard 0 block 92,730,034 and shard 1 block 94,978,278, each recorded at 11:25:37 p.m. UTC on Aug. 11, earlier than restarting the community from substitute databases constructed round these checkpoints.
https://t.co/EKDqnqTuDk
— Concord 💙 (@harmonyprotocol) August 17, 2026
Beneath the plan, new blocks would start at heights 92,730,035 on shard 0 and 94,978,279 on shard 1. Concord stated shopper model v2026.1.2 has been configured to reject the irregular block hashes linked to the incident, stopping validators from accepting the affected chain historical past after the restart.
The primary confirmed solid mint reached shard 0 at block 92,730,036, in accordance with the community. Block 92,730,035 contained no common or staking transactions, incoming receipts or fuel utilization, whereas its state remained unchanged from block 92,730,034.
Concord stated it chosen block 92,730,034 to supply a one-block security buffer. The database, restoration scripts and validator procedures had additionally been ready and reviewed round that block, whereas altering the checkpoint at a late stage may go away validators working from totally different restoration targets.
Shard 1 was not the place the solid mint occurred. Concord stated its corresponding checkpoint was included as a precaution utilizing the identical timestamp.
Concord rollback would use substitute databases
The restoration plan would exchange the affected shard databases as an alternative of utilizing Concord’s current in-place rewind perform.
In accordance with the group, the community’s –revert perform primarily strikes chain heads and doesn’t absolutely clear later receipts, indexes, snapshots and cross-shard info. Leaving a few of that information behind may protect an assault route or trigger validators to achieve totally different states.
Concord stated a substitute database offers validators a single reviewed state from which to renew consensus.
The group additionally thought of burning or repairing the solid ONE straight, however stated the tokens had already handed by exchanges, decentralized trade swimming pools, contracts and quite a few wallets. Eradicating property at particular person locations may subsequently have an effect on funds belonging to unrelated customers.
A blacklist was rejected as a result of it might go away the solid provide in existence whereas doubtlessly limiting wallets holding official property. Selectively replaying transactions was additionally dominated out as a result of the state of the substitute chain would differ from the discarded chain, that means equivalent transactions may produce totally different outcomes.
Token migration was an alternative choice reviewed by Concord, however the group stated it might trigger considerably extra disruption.
The choice comes after one other blockchain confronted an analogous selection following an exploit. In December 2025, Move revised rollback plans following a $3.9 million execution-layer exploit, dropping an preliminary full rollback proposal in favor of focused token burns after bridge operators and different contributors raised issues in regards to the impact on official exercise. crypto.information reported on the time that Move additionally deliberate a phased community restart and restrictions on flagged accounts.
Greater than 109,000 transactions face removing
Concord’s rollback would discard all blocks created after the chosen checkpoints, together with common transactions made by customers throughout the affected interval.
To measure the influence, the group constructed a shard 0 archive protecting blocks 92,730,035 by 92,871,662. The dataset contained 141,628 consecutive blocks, 109,126 common transactions and 315 staking transactions, with 109,441 actual transaction-to-receipt matches.
Concord stated it checked parent-hash continuity and receipt completeness all through the archived vary.
Automated exercise accounted for a lot of the transaction depend. Of the 109,126 common transactions, 104,545, or 95.80%, have been categorized as automated. DEX automation represented 99,863 transactions, together with 75,430 profitable swaps and 11,804 failed bot makes an attempt.
In consequence, Concord cautioned that the variety of discarded transactions shouldn’t be handled because the variety of affected customers.
The group additionally examined whether or not some common transactions could possibly be safely restored after the rollback. Solely 22 have been easy native transfers with out an apparent dependency within the obtainable information, however Concord stated even these couldn’t routinely be thought of protected for replay.
One other 860 native transfers raised questions involving balances, funding sources, nonces or later spending. An additional 80,630 transactions trusted contract or blockchain state, whereas 27,614 have been failed transactions, incident-linked exercise or actions involving exchanges, bridges and consolidation routes.
All 315 staking transactions additionally rely on chain and epoch state, in accordance with the replace.
Concord stated balances, nonces, token approvals, swap deadlines, liquidity pool reserves and staking circumstances would change as soon as the substitute chain begins. Beneath that altered state, a transaction that beforehand failed may succeed, whereas a swap, approval or staking transaction may generate a unique consequence.
Full EVM traces are additionally unavailable by the RPC information used within the evaluate, leaving inner contract transfers and storage modifications topic to application-specific evaluation.
Cast ONE moved by exchanges, swimming pools and bridges
The investigation has individually mapped the motion of the newly created ONE throughout the community.
In accordance with Concord, one pockets concerned within the solid mint tried 534 transfers of 5 billion ONE every inside 106 seconds. A complete of 477 transfers succeeded, shifting 2.385 trillion ONE.
Investigators created a time-ordered graph starting with all wallets related to the solid mints, separating transactions signed by these wallets from profitable transfers, failed makes an attempt and subsequent actions by different addresses.
The traced exercise was checked towards blocks, transaction receipts and balances by shard 0 block 92,805,850. Concord stated the funds reached standalone wallets, trade accounts, DEX routers and swimming pools, liquidity supplier positions, bridge contracts, wrapped ONE, staking wallets and high-volume service wallets.
When solid ONE grew to become blended with different property, the tracing mannequin adopted transfers chronologically and capped the quantity attributed to the solid tokens at every pockets’s obtainable stability. In accordance with the group, the tactic was meant to forestall the identical tokens from being counted repeatedly as they moved between addresses.
An earlier mannequin traced greater than 99.9% of the solid ONE to a pockets or service boundary, whereas a later model reconciled nearly the entire quantity throughout these boundaries and transaction charges on the chosen cutoff.
Concord burdened that route protection doesn’t imply investigators can determine the people controlling each vacation spot. Trade accounts, swimming pools, contracts and different service clusters can comprise funds belonging to many customers.
The quantity that may be safely destroyed is smaller nonetheless, in accordance with the group. Cast tokens left untouched in a standalone pockets could also be attainable to isolate, whereas ONE that entered an trade pockets, liquidity pool, bridge, staking place or one other shared stability may now not be eliminated in full with out risking unrelated property.
A comparable drawback has surfaced in different token-minting assaults. In June, Humanity Protocol disclosed that compromised administrative keys allowed attackers to take management of bridge infrastructure and mint further H tokens on BNB Good Chain. The protocol halted affected bridge operations and coordinated with exchanges and regulation enforcement whereas investigators tracked the stolen property.
Investigation continues alongside validator restoration
Concord stated it has made preliminary progress towards tracing the hacker and is working with exchanges, bridges and regulation enforcement to protect information and proceed the investigation.
An impartial third-party safety firm additionally reviewed the incident individually and corroborated the solid mint and the principle findings from the fund-flow evaluation, in accordance with the community.
Concord has handled a significant cross-chain safety incident earlier than. Its Horizon Bridge misplaced about $100 million in June 2022 after non-public keys controlling the bridge have been compromised. The mission subsequently labored with exchanges, regulation enforcement, and blockchain analytics corporations to determine the attacker, whereas elevating its hacker bounty to $10 million.
Funds from that assault continued shifting months later. In January 2023, on-chain investigators tracked stolen ETH by lots of of addresses, whereas Binance and Huobi froze accounts linked to the motion and recovered 124 BTC.
For the present incident, Concord stated it’s working with exchanges and bridges to evaluate the impact of discarding post-checkpoint exercise and decide how affected events might be dealt with. The group stated all blocks after the checkpoints could be eliminated below the proposed restoration, together with common transactions that have been unrelated to the solid mint.
