What happened
On 23 April 2026, an attacker exploited GiddyVaultV3 on Ethereum for an estimated $1.3 million. The vault's EIP-712 authorization signed swap calldata but omitted the route's aggregator, token addresses, and amount. By substituting those unsigned fields while retaining valid signed data, the attacker redirected token approvals to an attacker-controlled contract and removed strategy-held assets.
Every execution-relevant swap field must be bound by authorization. Here, unsigned fields controlled the approval target, external call target, asset, allowance, and output check, allowing a valid signature to authorize a materially different action.
How it happened
- GiddyVaultV3 signed only
SwapInfo.data, whileaggregator,fromToken,toToken, andamountremained outside the EIP-712 digest. - The attacker retained valid signed data but selected strategy-held LP tokens as the input asset, an attacker contract as the aggregator, and a controlled allowance amount.
- The vault approved that contract and called it; the attacker then used transferFrom to remove the assets.
- A fake output token made the final nonzero-balance check pass without a legitimate swap.
- The core issue was incomplete signature coverage, not a broken signature primitive, flash loan, or price manipulation.
Protocol details
Evidence
Understand the attack patterns
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