Zano Restores Blockchain Before Hard Fork 6 After Vulnerability
The Zano project released an emergency version that rolls the chain back to block 3,833,000 from August 26, 2026, before Hard Fork 6 was activated. Approximately one month of transactions has been removed from the canonical history.
Zano blockchain restoration was carried out by emergency software following a vulnerability in the Gateway Addresses feature. The chain has been rolled back to block 3,833,000 from August 26, 2026, returning it to the state before Hard Fork 6 was activated. Transactions from the original branch created after this block are no longer part of the chain followed by the emergency version.
The project team said the vulnerability enabled the unauthorized issuance of the ZANO coin and the fUSD asset. The GitHub release describes the intervention as a response to an attack that affected the supply of Zano’s native coin and network assets.
Zano blockchain restoration removes approximately one month of history
The rollback means the network’s canonical history returns to the block from August 26, 2026. Along with the unauthorized assets created, legitimate transactions made after this block were also removed from the new canonical branch.
Node operators, miners, stakers, exchanges, and other services must update their software to follow the restored branch. Until they do so, they may be working with the original history, which the emergency version does not consider valid.
For users, it is important to verify balances and transaction status on the restored network before sending another payment. Particular attention is needed for services or counterparties that have already settled payments from the affected period outside the Zano network.
The issue involved Gateway Addresses
Gateway Addresses were activated together with Hard Fork 6 at block 3,833,000. Zano has not yet disclosed the technical cause of the vulnerability, the extent of the unauthorized issuance, or the attacker’s identity.
The project also claims that spend keys, wallets, and the privacy of ordinary transactions were not compromised. However, this claim is not yet accompanied by an independent audit or a public technical post-mortem.
The extent of the financial damage is also unknown. Zano announced compensation, but it has not yet published the compensation rules or the methodology for calculating them.
What will be important next
- A public technical analysis of the incident and a fix for the Gateway Addresses logic.
- Publication of the amount of unauthorized ZANO and fUSD issued.
- Confirmation that exchanges, bridges, wallets, and payment services have moved to the restored branch.
- Independent security verification of claims that keys and transaction privacy were not affected.
It has not yet been independently confirmed whether all external services have completed the migration. Users should therefore verify which branch their wallet or service is following before carrying out operations.
Sources
- Zano Forum — Security update and coordinated upgrade – Zano team announcement about the vulnerability, the restart from block 3,833,000, the invalidation of affected transactions, and the planned compensation.
- hyle-team/zano — GitHub Releases – The emergency version states that the chain was rolled back to block 3,833,000 from August 26, 2026, in response to an attack affecting the supply of ZANO and assets.
- Zano Monthly Project Update #23 — August 2026 – Confirms that Hard Fork 6 and Gateway Addresses were activated at block 3,833,000 on August 26.
- Cointelegraph – Independently describes the scope of the rollback and its operational consequences for users and services.
Verified and updated: September 28, 2026 06:21
