Harmony’s ONE sinks 40% after apparent 4B-token mint

Harmony’s ONE token dipped by about 39% on August 12 after data on the blockchain indicated the illicit creation of approximately 4 billion tokens. This could have rendered the current holders of the token nearly a quarter poorer and has also raised concerns over the security issues once again.

The mint was reported by the on-chain analyst Juiceberg. Meanwhile, Harmony said that it was in discussions with exchanges for freezing the funds related to the mint and that it was also preparing a patch and a possible rollback. However, the project did not confirm the minting of 4 billion tokens nor disclose the cause behind it.

Four billion tokens conjured from empty blocks

What makes this incident even more serious is perhaps the volume being talked about. Juiceberg estimated that there had been the creation of around 4 billion ONE through what has been referred to as “empty blocks.” With around 15 billion ONE already in circulation before the incident means that approximately 26% of the total supply was involved.

Harmony exploited as on-chain data reveals unauthorized 4B ONE mint (26% of supply) via empty blocks, with 2.8B quickly funneled to exchanges as price crashed while totalSupply endpoint hides the inflation $ONE

— Juiceberg (@the_juice_berg) August 12, 2026

However, the “empty blocks” do not explain how the mint happened. The normal block reward mechanisms of Harmony provide a reward of 7 ONE for each confirmed shard block. Therefore, if a mint amounting to multi-billion ONE had occurred, this would imply errors or corruption in the network accounting, state transition, reward, or validation mechanisms.

Harmony has not identified the component that has problems yet. Therefore, it still cannot determine the details of the incident.

Most of the minted supply is already being traced to exchanges

The selling pressure has already started to hit. Juiceberg has estimated that almost 2.8 billion ONE has gone to exchanges and 115 million ONE is left to sell on-chain. Harmony has not yet verified those figures.

It is worth mentioning that getting the tokens to the exchange does not imply they have been sold. In fact, they might stay in deposit wallets or be changed or withdrawn even before any freezing request has been sent.

Harmony says it is pursuing freezes and a rollback

Where before Harmony asked exchanges only to cooperate and work with their systems, now it asks them to freeze and block the funds associated with four wallet pairs. Harmony also gave Harmony- and Ethereum-format wallet addresses connected to the attack.

We are asking all exchanges to block and freeze funds that traces back to these 4 wallet addresses:

one1uap8dx2z0qsjxqthm5flgcxkeepsz3gsrghnfn
0xe7427699427821230177dd13f460d6ce43014510

one17u300a40ll5wphd8kj5hktryhdjq3ml9f4phy4
0xf722f7f6afffe8e0dda7b4a97b2c64bb6408efe5… https://t.co/wiR6uQOazW

— Harmony 💙 (@harmonyprotocol) August 12, 2026

This action allows exchanges to know precisely which addresses are involved and to identify deposits linked to the particular mint, possibly. Thus, the exchange will be able to prevent any withdrawal of money or money transfer. However, Harmony did not inform the community about which exchanges the funds were sent to, the total amount received by them, and the amount of funds frozen.

It is worth mentioning that the project team worked on creating a patch and possible rollbacks. While the deletion of the attacker’s balance is relatively easy, the rollback is much more complicated because Harmony should understand the range of blocks to roll back and manage transactions in this range.

These two tools are completely different: exchanges can freeze their assets, and rollback changes the blockchain’s history.

Why the fallout stays mostly inside Harmony

The damage to ONE is severe, but broader contagion appears more limited. Harmony’s ecosystem is far smaller than during its 2022 peak, leaving less external liquidity through which a ONE supply shock could spread.

That does not make the incident insignificant. Billions of newly created ONE entering exchanges can still affect market makers, exchange risk systems and token holders.

The bigger issue is confidence. If Harmony cannot explain why billions of tokens entered circulation, investors have little reason to assume the same problem cannot happen again.

An echo of Harmony’s earlier token-minting bug

Unintended token-creation trouble has happened to Harmony before. Back in December 2023, Harmony revealed that a staking-logic vulnerability was behind the creation of 146.28 million ONE tokens for 74 delegator addresses. In this situation, matured undeliverables were not being deleted from the network’s state. This way, those same tokens could be distributed multiple times. To solve this issue, Harmony had to launch an emergency hard fork.

The newly revealed 2026 mint is about 27 times larger. Although these incidents are not exactly alike, it is still important to note that each demonstrates how flaws in accounting logic may cause the creation of new tokens, as opposed to the stealing of the existing ones.

This becomes especially important when compared to the 2022 Horizon bridge hack on Harmony. In this case, hackers managed to steal around $100 million worth of assets from the bridge, and this crime was later attributed to the Lazarus Group (North Korea).

The current situation is even worse, since it targets the core of the blockchain’s monetary accounting system. Now, the key questions are how many ONEs have been created, how many of them have been frozen, and what vulnerabilities caused this minting to happen.

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