hack or exploit

Tranche Vault on Avalanche Drained of 1.01 Million USDC

0Importance
closedStatus
2News media
5Pieces
Published
Updated
Since then
4 new reports

An Avalanche tranche product tied to Valinor Digital, OatFi and Fence Finance was drained in late October, with reports converging on about $1.01 million in USDC. Separate coverage describes two different accounting paths in the same incident: one involving inflated tranche shares and another involving a scheduled payment being treated as settled at a UTC day rollover.

Key claims & sources

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The Tranche Vault was linked to Fence Finance and Valinor Digital on Avalanche, and the reported exploit date was 2026-10-28, with losses of about $1.01 million.
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A settlement flaw in a TranchePool on Avalanche counted a scheduled principal payment as received at UTC day rollover, which let an attacker withdraw about $1.013 million in USDC again.
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Blockaid said a flash loan was used to mint inflated tranche shares and redeem USDC from an Avalanche Tranche Vault, and a balance check showed no funds left in the identified contract.
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Blockaid said the attack happened on the evening of Tuesday, Oct. 27, ET, and described the exploit as ongoing while it tagged Valinor Digital and Fence in its alert.

What it means

Tranche vaults split deposits into risk layers, a structure borrowed from traditional securitization and increasingly used in DeFi credit products that package real-world or on-chain loans. The Avalanche vault tied to Valinor Digital, OatFi and Fence Finance followed this model, with Fence and OatFi supplying the underlying credit logic. Flash loans, which let an attacker borrow and repay enormous sums within one transaction, have been a known attack vector since the 2020 bZx exploits and remain a recurring tool against share-pricing mechanisms.

Depositors in the affected pool cannot withdraw their USDC, and the Avalanche Builder Hub has told users not to deposit into the identified contract while it investigates. Valinor Digital, OatFi and Fence Finance now face the task of tracing roughly $1.01 million in losses, reconciling two conflicting technical explanations, and rebuilding trust with liquidity providers before relaunching. Other protocols using similar tranche-settlement logic gain a concrete reason to audit how they timestamp scheduled payments.

Two accounts of the same breach being reported in parallel, one blaming inflated share minting via flash loan and another blaming a UTC day-rollover settlement flaw, is itself a warning sign about how little clarity even security firms have in the first hours after a DeFi hack. Composability that lets a flash loan interact with a credit pool's internal accounting was always the point of open DeFi, yet here it becomes the attack surface, exposing how fragile tranche logic remains once real money sits behind it.

Blockaid called the exploit 'ongoing' as of its alert tagging Valinor Digital and Fence on X, so the immediate marker to watch is whether either company publishes a formal postmortem confirming which of the two mechanisms, inflated shares or payment-timing, actually drained the funds. A follow-up from the Avalanche Builder Hub on whether the contract is patched, paused permanently, or relaunched will determine if depositors see any path to recovering the $1.01 million.

Market reaction i

AvalancheAVAX it is the asset of the company or protocol in the event
first headline
+0.4% 2 h before
+0.2% 4 h after
$8.96price at publication
12data points

The move was larger before the first headline than after. That is an observation, not an explanation: the market also moves on things nobody publishes.

Coverage timeline

Every piece in order, with the time its news medium declares — if it is not believable we use ours and say so — and what it added to what was already known at that point. Arriving first is not the same as adding something.

first
Oct 28 01:11
The Defiant scoop
Breaks the event
+3 h 35 m
Oct 28 04:46
+3 h 35 m
Oct 28 04:46
+12 h 58 m
Oct 28 14:10
The Crypto Guardian context
Its angle: infrastructure, administrator, distinguished
+13 h 3 m
Oct 28 14:15

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