Chainlink Oracle Security Checklist

The definitive guide to auditing price feed integrations in DeFi protocols

Vulnerabilities Found

Protocols Analyzed

$5M+

Potential Bounties

Checklist Progress

Staleness ValidationCRITICAL

✓

Check for updatedAt timestamp validation

Ensure the oracle checks that price data is recent. Stale prices during volatility caused the $116M Mango Markets exploit.

✓

Verify answeredInRound >= roundId

This check ensures the answer was provided in the current or a later round, preventing stale round data.

✓

Confirm MAX_STALENESS threshold exists

Look for a configurable staleness threshold (typically 1 hour for major pairs, 24h for stablecoins).

VULNERABLE PATTERN
// No staleness check - found in SparkLend, Radiant
(, int256 answer,,,) = priceFeed.latestRoundData();
return uint256(answer);

SECURE PATTERN
(uint80 roundId, int256 answer,, uint256 updatedAt, uint80 answeredInRound) = priceFeed.latestRoundData();
require(answer > 0, "Invalid price");
require(block.timestamp - updatedAt < MAX_STALENESS, "Stale price");
require(answeredInRound >= roundId, "Stale round");

L2 Sequencer CheckHIGH

✓

Check for sequencer uptime feed (L2 only)

On Arbitrum, Optimism, Base, and other L2s, verify the sequencer is online before trusting prices.

✓

Verify grace period after sequencer restart

After a sequencer comes back online, oracles need time to update. Enforce a grace period.

L2 SEQUENCER CHECK
(, int256 answer, uint256 startedAt,,) = sequencerFeed.latestRoundData();
bool isSequencerUp = answer == 0;
uint256 timeSinceUp = block.timestamp - startedAt;
require(isSequencerUp, "Sequencer down");
require(timeSinceUp > GRACE_PERIOD, "Grace period not passed");

Price Bounds & SanityHIGH

✓

Check for minimum price bounds

Ensure prices cannot go below a reasonable minimum (prevents manipulation attacks).

✓

Check for maximum price bounds

Prevent absurdly high prices that could enable oracle manipulation.

✓

Verify answer > 0 check exists

Zero or negative prices should always be rejected.

Decimal HandlingHIGH

✓

Verify correct decimal conversion

Chainlink feeds return 8 decimals for USD pairs, 18 for ETH pairs. Check scaling logic.

✓

Check for Ray/Wad conversion errors

Found in Aave V4: 1e18 vs 1e27 scaling errors can make bad debt unrepayable.

Fallback & RecoveryHIGH

✓

Check for fallback oracle

If primary oracle fails, is there a backup (TWAP, secondary Chainlink feed)?

✓

Verify try/catch around oracle calls

Oracle reverts should not brick the protocol. Proper error handling is essential.

Found a Vulnerability Using This Checklist?

See our database of 19 vulnerabilities across 7 major DeFi protocols for submission examples.

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