Chainlink recommends that all Optimistic L2 oracles consult the Sequencer Uptime Feed to ensure that the sequencer is live before trusting the data returned by the oracle.
Vulnerability Detail
If the Arbitrum Sequencer goes down, oracle data will not be kept up to date, and thus could become stale. However, users are able to continue to interact with the protocol directly through the L1 optimistic rollup contract.
Even if there is a backup uniswap price feed if no problem is detected, the back up probably will not be used.
As a result, users may be able to use the protocol while oracle feeds are stale.
Impact
If the Arbitrum sequencer goes down, the protocol will allow users to continue to operate at the previous (stale) rates.
AlexCzm
medium
No check for active Arbitrum Sequencer
Summary
Chainlink recommends that all Optimistic L2 oracles consult the Sequencer Uptime Feed to ensure that the sequencer is live before trusting the data returned by the oracle.
Vulnerability Detail
If the Arbitrum Sequencer goes down, oracle data will not be kept up to date, and thus could become stale. However, users are able to continue to interact with the protocol directly through the L1 optimistic rollup contract. Even if there is a backup uniswap price feed if no problem is detected, the back up probably will not be used.
As a result, users may be able to use the protocol while oracle feeds are stale.
Impact
If the Arbitrum sequencer goes down, the protocol will allow users to continue to operate at the previous (stale) rates.
Code Snippet
https://github.com/sherlock-audit/2023-04-jojo/blob/6090fef68932b5577abf6b5aa26eb1e579353c57/smart-contract-EVM/contracts/adaptor/chainlinkAdaptor.sol#L43-L55
Tool used
Manual Review
Recommendation
Follow the Chainlink recomandations and use a sequencer uptime feed.
Duplicate of #101