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Invest Independently confirmed2 publishers 3 min read Published Updated

Zano's one-day rollback grew into a month-long rewind to before Hard Fork 6

Zano restarted its privacy chain at block 3,833,000, erasing about a month of history to purge ZANO and fUSD minted through a Gateway Address bug. Legitimate transfers made since the feature went live are voided too, pending a claims process Zano has yet to publish.

The Investor · Invest desk

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What happened

  • On September 25 Zano told users to freeze activity in ZANO and Confidential Assets and said it would unwind roughly 24 hours of chain history.
  • Gateway Addresses had gone live with Hard Fork 6 at block 3,833,000 on August 26, after more than a year of development work.
  • Zano said transaction privacy was unaffected and that no spend keys or wallets were compromised by the flaw.
  • Recovery requires nodes, miners, stakers, exchanges and other services to adopt the update before the restarted chain takes hold.
  • ZANO fell about 20 percent after the first announcement, according to reports cited by Crowdfund Insider.

Why it matters

  • What doesn't add up contradiction The rollback window widened about thirtyfold between the first plan and the restart, so anyone who traded or credited deposits on the one-day figure acted on a scope that turned out to be wrong.
  • What it costs cost Anyone who sent or received ZANO or fUSD after the fork now has to reconcile balances, and is made whole only through the claims process the team has promised.
  • What it sets up precedent Van Welzen argued that letting exploited coins keep their value would invite every future attacker, so the next supply error on this chain can be expected to meet another rewind.
  • Who has to decide decision Exchanges crediting Zano deposits have to rethink how many confirmations they trust, now that blocks as much as a month deep were discarded.

The first plan unwound about a day [20]. The restart went to block 3,833,000, immediately before Hard Fork 6 [7], the height at which Gateway Addresses switched on [9]. From the August 26 fork to the September 25 announcement is 30 days, so the cut widened roughly thirtyfold from one statement to the next [22]. Neither report explains why. Two readings fit: the unauthorized minting started well before the final day, or the team stopped trusting any state produced under the new rules. Going back to the fork height itself, the one block known to predate every Gateway Address, suggests the team could not place the start of the minting any later.

The feature was built so bridges, exchanges and payment services could integrate more easily [4]. An ordinary Zano address shows no readable balance, and a service has to scan the chain and rebuild holdings from private outputs [5]. A Gateway Address instead carries an account-style public balance that an integrator can query directly [6]. Zano says the flaw in public Gateway Addresses affected asset issuance, including fUSD [10]. It has not released a post-mortem or said how much extra supply was created [1][3], and outside speculation that transactions mixing gateway and confidential outputs were the path is unconfirmed, Crowdfund Insider reported [12].

So Zano is giving up the whole live history of its integration feature, plus a month of everyone else's transactions [13], and is not patching forward with an unknown quantity of extra ZANO and fUSD still circulating [3]. On a chain that pays a fixed 1 ZANO a minute and burns every fee [21], the discarded window held about 43,200 ZANO of scheduled block rewards, 1,440 a day for 30 days [23]. Those rewards go with the blocks that paid them [23].

"Doing nothing meant unauthorized ZANO and fUSD in circulation without limit, diluting every holder and breaking the most basic promise a currency makes: a fixed supply," said Quinten van Welzen, Zano's head of marketing and growth [17]. "Restarting the chain from before Hard Fork 6 costs a month of history, and it costs trust, which we'll have to earn back," he said [19].

The sell-off came on the one-day plan [24][20], before anyone knew the cut would be a month. That was a price moving on a supply scare. The value of a ZANO now depends on whether the reset supply holds and on who absorbs the lost month, and the team says it will publish a reimbursement and claims process to settle the second question [8].

With fast adoption and a claims process that covers payments settled on other chains, holders get the fixed supply back for the cost of a month's reconciliation. Slow adoption leaves the network frozen until the majority needed to activate the upgrade is assembled [16]. The harder case is a claims process that leaves out payments already settled on other chains [14], which would put the cost of the feature's failure on the integrators it was built for [4]. I think that third case is where lasting damage to Zano's exchange relationships would come from, because claims are the only remedy for money the rollback cannot reach [14][8]. The view that Zano could not bound the damage more tightly is wrong if the post-mortem shows the minting began inside the final day.

What to watch

  • The post-mortem: whether the minting began near the August 26 fork or inside the final day, and how much ZANO and fUSD it created.
  • Whether the reimbursement and claims process covers payments already settled on other chains during the voided month.
  • Whether a patched Gateway Addresses returns in a later fork, or integrators go back to scanning private outputs.

Information, not investment advice. This story is general information about companies and markets, drawn from cited reporting. It is not a recommendation to buy, sell or hold any security; check the cited sources before acting.

Clarity's read

What the record supports and how the coverage leans. The claims behind it follow.

Reality

Evidence62
Adoption
Not scored
Hype gap+15
Incentives70
Confidence60
Why these scores

Claim ledger

Ranked by verification strength, evidence, and original report placement.

  1. [1]

    Zano had not released a post-mortem at the time of Cointelegraph's publication.

    Reported SupportedView cited source
  2. [2]

    Zano rolled back approximately a month of blockchain history after a Gateway Addresses vulnerability allowed unauthorized ZANO and Freedom Dollar (fUSD) to enter circulation, according to its core team.

    Reported SupportedView cited source
  3. [3]

    Zano has not published the exact quantity of extra assets created.

    Reported SupportedView cited source
  4. [4]

    Gateway Addresses were developed to make it easier for bridges, exchanges and payment services to integrate with Zano.

    Reported SupportedView cited source
  5. [5]

    Ordinary Zano addresses do not expose a readable balance; a service must scan the chain and reconstruct holdings from private outputs.

    Reported SupportedView cited source
  6. [6]

    Gateway Addresses behave like account-style addresses with a public balance that integrators can query directly, while everyday user wallets remain fully private.

    Reported SupportedView cited source
  7. [7]

    The Zano blockchain has been restarted at block 3,833,000, immediately before Hard Fork 6, which introduced the affected feature, the team said Sunday.

    Reported SupportedView cited source
  8. [8]

    The team said it is working to account for any losses and will publish a reimbursement and claims process.

    Reported SupportedView cited source
  9. [9]

    Gateway Addresses went live with Hard Fork 6 at block 3,833,000 on August 26 after more than a year of work.

    Reported SupportedView cited source
  10. [10]

    Zano said the core team found a vulnerability in public Gateway Addresses that affects asset issuance, including the confidential stablecoin fUSD.

    Reported SupportedView cited source
  11. [11]

    Zano said transaction privacy was not broken and that spend keys and wallets were not compromised.

    Reported SupportedView cited source
  12. [12]

    Outside observers have speculated that mixed transactions combining gateway outputs with confidential outputs may have been involved, but the project has not confirmed the precise code path.

    Reported SupportedView cited source
  13. [13]

    The rollback invalidates a month of legitimate transactions along with the unauthorized tokens; transactions made in that period will no longer appear on the recovered chain and may need to be reconciled.

    Reported SupportedView cited source
  14. [14]

    The rollback cannot reverse payments already settled on other blockchains.

    Reported SupportedView cited source
  15. [15]

    The recovery requires participating nodes, miners, stakers, exchanges and other services to adopt the update, the team said.

    Reported SupportedView cited source
  16. [16]

    The upgrade needs majority consensus to activate.

    Reported SupportedView cited source
  17. [17]

    "Doing nothing meant unauthorized ZANO and fUSD in circulation without limit, diluting every holder and breaking the most basic promise a currency makes: a fixed supply," said Zano's head of marketing and growth Quinten van Welzen.

    Reported SupportedView cited source
  18. [18]

    "It would also tell every future attacker that exploited coins get to keep their value. No project survives that." said Quinten van Welzen.

    Reported SupportedView cited source
  19. [19]

    "Restarting the chain from before Hard Fork 6 costs a month of history, and it costs trust, which we'll have to earn back," said van Welzen.

    Reported SupportedView cited source
  20. [20]

    On September 25, 2026, Zano said a supply-integrity defect in its Gateway Addresses feature left developers little option but to unwind roughly 24 hours of chain history, and told users to freeze economic activity in native ZANO and Confidential Assets.

    Reported SupportedView cited source
  21. [21]

    Zano issues a fixed 1 ZANO block reward every minute and burns all transaction fees.

    Reported SupportedView cited source
  22. [22]

    The rollback window widened from about one day (the September 25 plan) to about 30 days (the August 26 fork height to the September 25 announcement), roughly thirtyfold.

    Derived Supported
  23. [23]

    The discarded window held about 43,200 ZANO of scheduled block rewards, which disappear with the discarded blocks.

    Derived Supported
  24. [24]

    Reports indicated ZANO fell about 20 percent after the announcement.

    Reported InsufficientView cited source

Sources

2 independent publishers whose own reporting we read for this story.

  1. cointelegraph.com

    2 articles · October 1, 2026

    Zano rolls blockchain back a month after Gateway Address exploit
  2. crowdfundinsider.com

    2 articles · October 2, 2026

    Privacy focused L1 Network Zano Plans 24-Hour Chain Rollback After Gateway Address Inflation Bug

Topics and entities

Topics

Entities

  • Quinten van Welzen