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FIGR_HELOC $1.06Zano rolls back a month of chain history after Gateway Address exploit
Zano restarted its chain at block 3,833,000 to remove unauthorized ZANO and fUSD, invalidating about a month of transactions.
The short answer
Zano restarted its chain at block 3,833,000, just before Hard Fork 6, which introduced Gateway Addresses. A flaw in that feature let unauthorized ZANO and Freedom Dollar enter circulation. The rollback removes those tokens but also erases about a month of legitimate transactions. Nodes, miners, stakers and exchanges must adopt software version 2.2.3.600, and no post-mortem or claims process has been published yet.
What happened
Zano restarted its blockchain at block 3,833,000, the block immediately before Hard Fork 6, which introduced Gateway Addresses. The core team said a vulnerability involving Gateway Addresses allowed unauthorized ZANO and Freedom Dollar (fUSD) to enter circulation, and that the chain has rolled back about a month of history.
Gateway Addresses were built to let bridges, exchanges and payment services manage funds through a single account-style balance instead of tracking separate transaction outputs. Registering a Gateway Address cost a one-time fee of 100 ZANO, which was burned, and records show at least two addresses were registered in the feature's first week.
Zano published software version 2.2.3.600 for the recovery. The recovery requires participating nodes, miners, stakers, exchanges and other services to adopt the update and follow the recovered chain. Ordinary wallet users can update without re-entering seed phrases.
MEXC suspended deposits and withdrawals for ZANO and FUSD while it works through the migration, and no restart time had been announced as of publication. The team said it is working to account for any losses and will publish a reimbursement and claims process.
Why it matters
Zano's head of marketing and growth, Quinten van Welzen, said doing nothing would have left unauthorized ZANO and fUSD in circulation without limit, diluting every holder and breaking the fixed supply promise. He also said restarting the chain from before Hard Fork 6 costs a month of history and trust.
The rollback invalidates a month of legitimate transactions along with the unauthorized tokens, so payments from that period no longer appear on the recovered chain and may need to be reconciled. It cannot reverse payments already settled on other blockchains.
Van Welzen said the team cannot force a rollback on its own and can only release software for node operators to adopt. He said funding for reimbursement will come from the development fund, team holdings and large holders, and that no new ZANO will be created to cover losses.
What the data shows
ZANO traded near $6.32 during the recovery, down about 12.85% over 24 hours, according to CoinMarketCap. The chain restart point was block 3,833,000, and the recovery release was version 2.2.3.600.
Background
Zano launched in May 2019 as a layer-1 blockchain focused on private payments. Its standard private transactions conceal senders, receivers, transferred amounts and asset types.
While it has a native token, ZANO, the blockchain also allows users to deploy and mint custom digital assets. Freedom Dollar (fUSD) is one such token that operates on the Zano blockchain.
What is still unclear
- Zano has not released a post-mortem at the time of publication.
- The team has not yet released a full technical report explaining exactly how the exploit worked, though it said normal wallet keys and transaction privacy were not affected.
- Early statements from the project described a shorter rollback while the scale of the issue was still being assessed.
- A formal reimbursement and claims process has not yet been published, and MEXC has not announced a restart time.
Questions readers ask
What happened in the Zano Gateway Address exploit?
A vulnerability involving Gateway Addresses let unauthorized ZANO and Freedom Dollar (fUSD) enter circulation, according to Zano's core team. The team restarted the chain at block 3,833,000 to remove those tokens.
Why did Zano roll back a month of blockchain history?
Zano said doing nothing would have left unauthorized ZANO and fUSD in circulation without limit, diluting holders and breaking the fixed supply promise. The rollback restores the supply but also removes a month of legitimate transactions.
How are ZANO users affected by the rollback?
Transactions from the affected month will not appear on the recovered chain and may need to be reconciled. Ordinary wallet users can update without re-entering seed phrases, while third-party platforms must update on their own schedule.
Will Zano reimburse users for losses?
Zano said it is working with affected projects to calculate losses, and a formal reimbursement and claims process has not yet been published. Van Welzen said funding will come from the development fund, team holdings and large holders, with no new ZANO created.
