Harmony ONE Hack: Blockchain Rollback Weighed After Hacker Mints 26% of Supply

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.