Incident All ledgers
Yearn Finance: $11.0m
Yearn Finance lost $11.0m on 5 February 2021. Ranked 187th of 1,272 crypto failures, with method, returned funds and comparable incidents.
- Date
- 5 February 2021
- Lost
- $11.0m
- Returned or repaid
- None recorded
- Target
- DeFi Protocol
- Category
- Oracle Manipulation
- Method
- Spot Price Manipulation
- Chains
- Ethereum
On February 4, 2021, an attacker used flash loans to manipulate exchange rates and exploit Yearn Finance's yDAI vault, which lacked sufficient slippage protection. The vault lost $11M; the attacker netted about $2.7M after $3.5M in fees.
Against the ledger
- It ranks 187th of the 1,272 incidents with a known loss, and 37th in 2021.
- It accounts for 16.8% of the $65.4m in known losses in February 2021.
- 159 incidents in the ledger are classified as Oracle Manipulation, for $894.1m in total. This one is 1.2% of that.
- The ledger records no returned funds.
Other incidents named Yearn
| Date | Target | Lost | Type | Method | Returned |
|---|---|---|---|---|---|
| 13 Apr 2023 | Yearn Finance | $11.5m | DeFi Protocol | Oracle Misconfiguration | — |
| 30 Nov 2025 | Yearn Ether | $9.0m | DeFi Protocol | Incorrect Share Accounting | — |
| 16 Dec 2025 | Yearn Finance | $300,000 | DeFi Protocol | Donation Attack | — |
Closest in size by the same method
| Date | Target | Lost | Type | Method | Returned |
|---|---|---|---|---|---|
| 28 Apr 2022 | DEUS Finance | $13.4m | DeFi Protocol | Spot Price Manipulation | — |
| 13 Apr 2023 | Yearn Finance | $11.5m | DeFi Protocol | Oracle Misconfiguration | — |
| 12 May 2022 | Venus Protocol | $11.2m | DeFi Protocol | Stale Oracle Price | — |
| 22 Feb 2026 | Blend Pools V2 | $11.0m | DeFi Protocol | Spot Price Manipulation | — |
| 11 Jul 2026 | Bonzo Lend | $9.1m | DeFi Protocol | Spot Price Manipulation | — |
All failures in 2021 · The failures ledger
Amounts are DefiLlama’s estimates and can change as incidents are revalued. Its returned figure can include money a company repaid itself, not only funds recovered from attackers. Source: DefiLlama.
Cite this Bitminer.io, “Yearn Finance, failures ledger”, data to 2 November 2026, https://bitminer.io/ledger/incident/yearn-finance-2021-02-05/. How this is built