Harmony (ONE) unauthorized mint hack — August 2026

An attacker minted about 4 billion ONE on the Harmony blockchain on 12 August 2026, roughly a 26 per cent increase on the 15 billion already in circulation. Harmony confirmed the exploit the same day after the X account Juiceberg flagged it. The chain's totalSupply endpoint did not reflect the new tokens, so the inflation was not visible where most tooling looks for it, and about 2.8 billion of the minted supply reached centralised exchanges before the market priced it in. Roughly 115 million were still sitting on-chain unsold.

ONE fell between 26 and 40 per cent depending on the window measured, trading near $0.0008 afterwards. Harmony pushed an emergency update to stop further minting, paused its token bridge, asked exchanges to freeze four associated addresses, and said it was weighing a chain rollback.

The dollar figure here needs reading carefully. It is the value of the minted supply at the post-disclosure price, which is the figure the reporting settled on; it is not a confirmed record of what the attacker took out. Nobody has published the realised proceeds, and they are probably lower than the nominal figure, because the price fell as the tokens were sold into it. The range given spans the minted supply at the pre-exploit price at the top and the exchange-bound portion at the post-crash price at the bottom.

Harmony has not published a technical root cause. No attribution has been established.