Incident Overview
On January 13, 2025, UniLend V2 (@UniLend_Finance) on Ethereum was hacked for approximately 61 stETH (~$200K).
The attacker exploited UniLend V2’s flawed sequence in redeemUnderlying, where LP tokens were burned and collateral was transferred before the pool’s token balances were updated. By depositing a large amount of USDC, the attacker secured an artificially high “lendBalance” calculation due to outdated health factor checks and rounding issues in getShareValue. Consequently, they withdrew their deposited USDC while retaining stETH collateral, netting approximately 61 stETH (~$200K) in the process.
Incident Report
Protocol Information
Market Context at Time of Hack
What the Attacker Needed to Succeed
Understanding the prerequisites for this type of attack helps auditors identify protocols that are most at risk and helps developers build better defenses.
What Auditors Should Check
If you're auditing a protocol with similar architecture to Unilend V2, these are the critical security checks that could have prevented this incident (January 2025).
- Verify all logic paths related to Redeem Process Exploit / Other are guarded by proper access controls and input validation
- Review privileged functions (owner, admin, governance) for potential abuse vectors - centralization risks should be documented and bounded with timelocks or multi-sigs
Master these auditing techniques with hands-on labs and real exploit scenarios in the Smart Contract Hacking course.
Free TrialProof-of-Concept Exploits
On-Chain Evidence & References
Sources & References
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