Harmony is considering rolling back its blockchain after an unknown attacker exploited a network vulnerability and minted nearly 4 billion ONE tokens: equivalent to roughly 26% of the cryptocurrency’s total supply.
On Aug. 11, the project’s team said it was working with cryptocurrency exchanges to identify, freeze and block funds linked to the incident.
The Layer-1 blockchain’s developers are also preparing a patch to address the vulnerability and evaluating whether the network could be restored to its pre-exploit state. Harmony has not yet disclosed the technical cause of the incident, the exact number of unauthorized tokens minted or how much of the newly created ONE reached exchanges.
What Is Known About the Harmony Exploit?
Harmony’s statement followed a post from the account Juiceberg, which claimed that unauthorized ONE tokens were minted through empty blocks.
According to Juiceberg’s analysis, approximately 2.8 billion ONE were rapidly transferred to exchanges as the token’s price began falling.
The account also estimated that the attacker still holds around 115 million ONE on-chain, representing roughly 2.9% of the estimated amount created during the exploit. The remaining tokens, according to the analysis, may already have been sold or remain in exchange deposit wallets.
These figures have not been independently confirmed, and Harmony has yet to provide a complete accounting of the affected supply.
ONE Price Drops More Than 50% After Exploit
The incident triggered heavy selling pressure in ONE, with the token falling more than 50% at one point. It remains down approximately 33.6% over the past 24 hours.
The sharp decline reflects concerns over both the sudden increase in circulating supply and uncertainty surrounding a possible blockchain rollback.
If billions of unauthorized tokens remain in circulation, the dilution could continue weighing on ONE. At the same time, reversing transactions would introduce a separate set of concerns around network governance and blockchain immutability.
Harmony Has Faced a Major Hack Before
The latest exploit comes more than four years after the June 2022 Horizon Bridge hack, which resulted in approximately $100 million in stolen cryptocurrency.
The FBI later attributed that attack to North Korea’s Lazarus Group.
The new incident therefore creates another major security challenge for a network that has already suffered one of the cryptocurrency industry’s most prominent bridge exploits.
Harmony is continuing to work with exchanges to restrict movement of the newly minted tokens while developers investigate the vulnerability and prepare a patch. The team is also evaluating potential rollback scenarios, although no final decision has been announced.
Any attempt to reverse the blockchain would likely require substantial support from validators and the wider Harmony community.
