Harmony said on Aug. 12 that it was working with cryptocurrency exchanges to stop and freeze funds after a suspected security incident on its Layer 1 network.
Summary
- Harmony is working with exchanges to freeze funds while developing patch and evaluating rollback options.
- Analyst Juiceberg reported roughly four billion ONE were minted without authorization through empty network blocks.
- About 2.8 billion ONE reportedly reached exchanges, while Harmony has not confirmed the amount publicly.
- ONE fell about 26% over 24 hours as trading volume surged above $36 million Wednesday.
- Harmony previously suffered a staking bug that unintentionally minted 146.3 million ONE during 2023 operations.
In a post, the team also said it was developing a patch and evaluating rollback options. It did not identify the root cause, confirm how many tokens were created or name exchanges that had frozen assets.
On-chain analyst Juiceberg reported an “unauthorized 4B ONE mint” through empty blocks. In separate analysis, the researcher said about 2.8 billion ONE were quickly routed to exchanges and later estimated that roughly 115 million remained available to sell onchain. Harmony has not independently confirmed those figures, so the amounts remain analyst estimates rather than an official assessment.
Harmony investigates reported 4 billion ONE mint
The reported mint would be unusually large relative to ONE’s existing supply. crypto.news data listed about 15 billion ONE in circulation on Wednesday. Four billion tokens would equal roughly 27% of that previously reported circulating amount, although the comparison does not establish Harmony’s supply after the suspected incident.
Juiceberg also claimed Harmony’s total supply endpoint “hides the inflation.” The project has not confirmed that assertion. Harmony’s statement was narrower, saying its team was coordinating with exchanges, preparing a patch and considering rollback options. It provided no public timetable for either step.
ONE price plunges as trading volume jumps
ONE sold off sharply as reports of the mint circulated. crypto.news showed the token near $0.00083, down about 32% over 24 hours, with trading volume around $36.9 million. Its market capitalization stood near $13.7 million when the data was checked.
The market move coincided with the reported incident, but available data does not establish how much selling came from addresses linked to the suspected attacker. Juiceberg’s claim that 2.8 billion ONE reached centralized exchanges would make exchange cooperation central to recovery efforts if those transfers are confirmed.
Harmony has faced unauthorized token creation before
This is not Harmony’s first incident involving unintended token creation. In December 2023, the project published a technical report saying a staking logic flaw caused 146.28 million ONE to be minted across 74 delegator addresses. Harmony responded with an emergency hard fork.
The report traced the flaw to undelegation logic after a validator commission change. Some matured undelegations were not cleared correctly from network state and were repeatedly paid across epochs, creating tokens outside intended issuance. Harmony activated its fix at block 51,118,080.
Harmony also has a history of larger security losses. As previously reported, attackers drained roughly $100 million from the Horizon Bridge in June 2022. The FBI later attributed the theft to North Korea’s Lazarus Group in an official notice.
The stolen assets later began moving through Tornado Cash as investigators attempted to trace them. Harmony subsequently proposed minting billions of new tokens for victim reimbursement, but withdrew that proposal after community resistance. That planned recovery mechanism was separate from the unauthorized mint now reported by Juiceberg.
The latest incident also comes after the network’s DeFi activity contracted sharply. In related coverage, user deposits had fallen 99% from their 2022 peak by February 2025 following years of ecosystem outflows.
What happens next for Harmony
The immediate questions are whether exchanges can identify and freeze the reported deposits, what flaw enabled any unauthorized mint and whether Harmony ultimately chooses a rollback. A rollback would require clarity around the affected block range and how legitimate transactions made during that period would be treated.
As of publication, Harmony’s public statement had not supplied those technical details or confirmed the 4 billion ONE figure. The next verified update will need to establish the root cause, amount actually created, quantity frozen by exchanges and whether the network will deploy a patch or pursue a rollback.
