# What Happened in the Aave Oracle Incident? Explaining the $27 Million Liquidation The Aave oracle incident refers to a critical vulnerability that occurred in the Aave lending protocol. Here's what happened: ## The Oracle Malfunction A price oracle failure caused incorrect price data to be fed into Aave's system. Oracles are essential components that provide real-time asset price information to DeFi protocols. When an oracle malfunctions or reports incorrect prices, it can trigger cascading liquidations. ## The $27 Million Liquidation Due to the faulty price feed, the protocol incorrectly assessed collateral values. This led to: - **Massive liquidations**: Users' positions were liquidated based on incorrect price data rather than actual market conditions - **$27 million impact**: The total value of liquidated positions reached approximately $27 million - **User losses**: Borrowers lost their collateral despite having adequate collateral ratios based on real market prices ## Key Issues - The oracle provider failed to deliver accurate pricing information - The protocol's safeguards were insufficient to prevent the liquidation cascade - Users had no time to adjust their positions before liquidations occurred ## Impact This incident highlighted critical risks in DeFi: - Over-reliance on single or vulnerable oracle sources - Need for better circuit breakers and safeguards - Importance of oracle redundancy and price verification mechanisms Aave subsequently implemented improvements to its oracle infrastructure and risk management systems to prevent similar incidents.

A configuration error in the oracle price system used by Aave triggered liquidations of approximately $27 million in positions on Tuesday after the system temporarily undervalued an important staked Ethereum asset used as collateral.

The incident involved Aave’s Correlation Asset Pricing Tool (CAPO), designed to limit price volatility between highly correlated assets. At the time of the error, the oracle reported the Wrapped Staked Ether (wstETH) rate at around 1.1939 ETH, significantly lower than the market rate of nearly 1.228 ETH, creating a gap of about 2.85%.

This price discrepancy was large enough to activate the automatic liquidation mechanism in Aave V3’s Efficiency Mode (E-Mode). In this mode, highly correlated assets can be borrowed against each other at higher loan-to-value (LTV) ratios. However, when wstETH was undervalued, many leveraged positions using this asset as collateral fell below safety thresholds and were liquidated.

Blockchain data shows approximately 10,938 wstETH across 34 accounts were liquidated in this event. Based on market prices at the time, the total value of collateral liquidated was around $26–27 million across the Ethereum Core and Prime deployments of the protocol.

Liquidators received a total of about 499 ETH from the event. This includes roughly 116 ETH in liquidation bonuses and fees, along with approximately 382 ETH resulting from the temporary mispricing that undervalued the collateral.

Despite the large wave of liquidations, the protocol did not incur bad debt. Aave’s liquidation mechanism functioned as designed, helping the platform maintain liquidity and financial stability even as the oracle temporarily provided incorrect price data.

The affected assets are related to Lido Finance, a staking platform for Ethereum that issues the wstETH token. This token typically appreciates relative to ETH as staking rewards accrue over time. Lido stated that the incident was not related to their staking infrastructure but stemmed from a misconfiguration in Aave’s internal oracle.

According to technical analysis by risk management partner Chaos Labs, the root cause was a mismatch between data update timing and the rate limit constraints within the CAPO smart contract.

The oracle contract limits the maximum increase in the snapshot rate to about 3% every three days to prevent price manipulation attacks. However, when the off-chain oracle attempted to update the rate based on a seven-day reference window, the contract restricted the rate increase but still updated the timestamp. This caused the system to calculate a maximum rate that was lower than the actual market rate for wstETH, leading to temporary undervaluation and triggering liquidations.

The issue was identified and fixed within a few hours. Risk administrators adjusted the snapshot rate to align with the update window, restoring the oracle’s price range to market levels.

As a precaution, Aave temporarily reduced the borrowing limit for wstETH to 1 token on both Core and Prime systems to prevent new leveraged positions while engineers verified the fix.

The protocol also recovered part of the funds from the liquidations. About 141.5 ETH was returned through the BuilderNet mechanism related to the oracle update, along with approximately 13 ETH in associated fees.

Aave founder Stani Kulechov stated that the scale of the incident was only about 0.00274% of the protocol’s total size and emphasized that the core system remains stable.

In a post on X, he mentioned that service providers are working on a compensation plan for affected users using the liquidation fees collected earlier.

Chaos Labs founder Omer Goldberg also confirmed that all affected users will be fully reimbursed. The recovered funds will be prioritized, and the remaining compensation—estimated at up to 345 ETH—will be drawn from the Aave DAO treasury.

The DAO’s dedicated teams are finalizing the reimbursement mechanism, with an official proposal expected to be submitted to the community soon.

Although quickly contained, this event highlights that configuration errors—even without malicious attacks—can cause significant impact in DeFi systems that rely on complex oracle logic and high-leverage lending markets.

The incident also underscores an important characteristic of modern DeFi infrastructure: even when a glitch causes tens of millions of dollars to be liquidated, protocols can still maintain solvency, recover some assets, and compensate users without needing to halt operations.