Last weekend, someone deposited $200,000 into a DeFi protocol and walked away with $25 million in ETH.

The protocol is Resolv. The asset is USR, a stablecoin pegged to the dollar.

USR minting works like this: you deposit USDC, then an off-chain service with a privileged key decides how much USR to mint for you. The smart contract enforces a minimum deposit of 100,000 USDC per transaction.

But there's no maximum on the output side.

No cap. No ratio to collateral. Whatever the key holder authorizes gets minted. The contract checks the floor, never the ceiling.

The attacker got the key. Two transactions:

100K USDC in → 50M USR out

100K USDC in → 30M USR out

80 million unbacked stablecoins. Minted through the protocol's own function, working exactly as designed.

The attacker dumped USR on decentralized exchanges. The price crashed from $1.00 to $0.20. The team paused all protocol functions.

Think of a bank teller with signing authority and no transaction limits. In traditional finance, every transfer above a threshold requires a second signature, a time delay, or both. Resolv had none of these. One private key. No multisig. No timelock. No on-chain sanity check on output amounts.

The contract executed perfectly. That's the problem.

The security model was: "this key won't leak." The whole protocol's solvency depended on that one assumption.

Resolv held around $95 million in TVL before the exploit. The protocol is now paused, with assets well below outstanding liabilities.

One key. No ceiling. $25 million gone.