Oracles: which price controls the contract?

An oracle brings external information into a contract's decision process. For lending and derivatives, the relevant information is often a price. The security of the application depends partly on how that value is produced and how the application responds when it is delayed or unavailable.

Trace the dependency

Identify the reference markets, aggregation method, update conditions and handling of stale values. A contract may execute correctly using an inappropriate input. A low-liquidity market can be a poor foundation for a large lending exposure even if its quoted trades are real.

Compare the price used for liquidation with the prices a user can actually trade. A dashboard may show a different source or refresh time. During an incident, preserve the exact feed values and timestamps rather than relying on a later chart.

The defensive question is whether the system's limits and fallback behaviour fit the assets and markets involved. This guide does not provide a method for manipulating a feed. See liquidations and dependencies across protocols.

Sources

1. Chainlink: data feeds
2. MASTR: Crypto Survival Guide, four original panels

Research checked 5 September 2026. Historical cases retain the date and legal status of the cited record.