Harmony Blockchain Hacked: Fake Tokens Erased in Massive Rollback Effort

Harmony's blockchain has been hit by a massive hack that created over 4 billion fake ONE tokens, roughly 26% of the token's supply. The attacker exploited a flaw in how the network checks cross-shard receipts to process the same receipt more than once, creating tokens out of thin air.

The company has published a detailed rollback plan to erase the effects of the attack, which will discard every transaction confirmed on the network since August 11, 2026. All legitimate user activity along with the fraud will be deleted.

Harmony's new client software, v2026.1.2, will refuse to accept the block hashes tied to the hack, and the network will start creating new blocks from heights 92,730,035 and 94,978,279. The company chose this specific time because the first fake tokens appeared in the very next block on Shard 0.

The team has rejected other solutions, including burning the fake tokens, blacklisting them, or using a built-in revert tool to move the chain head. An independent security firm reviewed the hack and agreed with the rollback solution.