What happened
Moonwell's wrsETH market on Base accepted a faulty oracle price that dramatically overstated collateral value. An attacker supplied a tiny amount of wrsETH and borrowed assets far beyond its real value, leaving the lending market with bad debt.
Technical root cause
Moonwell used an erroneous wrsETH/ETH feed value in collateral calculations. The official account establishes exploitation of an oracle malfunction, without establishing that the attacker caused the faulty reading.
How it happened
- Moonwell multiplied its wrsETH/ETH and ETH/USD feeds to value collateral.
- The wrsETH/ETH feed returned an erroneous exchange rate, making a small deposit appear extremely valuable.
- The attacker borrowed cbXRP, EURC, USDC, AERO, wstETH and cbETH across repeated transactions, then swapped the assets to WETH.
- Moonwell restricted supply and borrowing, quarantined wrsETH markets, and replaced their oracles before restoring other borrow caps.
Protocol details
Classification
Borrowing and Lending / Protocol Logic / Oracle Manipulation
Protocol Type
Lending
Implementation language
Solidity
Protocol links
Website
@MoonwellDeFi
Security review history
- Halborn View report
Evidence
Proof of concept
1 availableSources
- report Twitter/X Alert x.com
- report @MoonwellDeFi incident report x.com
- report @getfailsafe incident report x.com
- analysis Website reference halborn.com
- analysis DeFiLlama defillama.com
- analysis wrsETH Oracle Malfunction 11/4/25 forum.moonwell.fi
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