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Harmony is considering rolling back its blockchain after an exploit reportedly created about 4 billion ONE tokens without authorization.
The project said on August 12 that it is working with exchanges to freeze related funds while developing a patch and reviewing rollback options. Harmony has not confirmed the exact amount created, disclosed the root cause or said how much ONE reached exchanges.
The reported 4 billion ONE would represent more than one-quarter of the roughly 15 billion tokens that existed before the incident.
Analyst Traces 2.8B ONE Toward Centralized Exchanges
On-chain analyst Juiceberg reported that roughly 4 billion ONE were created through empty blocks before about 2.8 billion tokens moved toward centralized exchanges.
A later update estimated that approximately 115 million ONE remained available on-chain, or about 2.9% of the reported unauthorized issuance. Harmony has not independently confirmed those figures.
Harmony instead identified four addresses linked to the incident and asked exchanges to block and freeze funds traced back to them.
Emergency Update Aims to Stop Further Unauthorized Minting
Harmony told network operators to install an emergency software update intended to prevent additional unauthorized minting. The project also paused its token bridge while working on how to address ONE already created during the exploit.
A rollback remains only one option. Harmony has not published a proposed rollback height, implementation process or timetable.
Reverting the chain to an earlier state could also remove legitimate transactions confirmed after the affected blocks, meaning any proposal would need to specify how that activity would be handled.
2023 Staking Bug Previously Created 146.3M ONE
Harmony previously experienced an unintended token-creation incident in December 2023. A staking logic flaw repeatedly paid matured undelegations and created approximately 146.28 million ONE across 74 addresses. Harmony responded with an emergency hard fork and temporary address blacklisting.
The network was also hit by the Horizon bridge exploit in June 2022, when attackers stole nearly $100 million in crypto assets.
Harmony’s immediate response remains focused on stopping further unauthorized issuance and freezing funds at exchanges. The project has not disclosed the current exploit’s root cause or committed to a rollback.
