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Last updated: July 01, 2025

SCWE-085: Misuse of Oracle Min/Max Price Band Without Validation

Stable Version v0.0.1

This content is in the version-(v0.0.1) and still under active development, so it is subject to change any time (e.g. structure, IDs, content, URLs, etc.).

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Description

This weakness occurs when smart contracts consume price oracle data (e.g., from Chainlink) without verifying whether the returned price falls within an expected or trusted range (e.g., minPrice/maxPrice). Oracles may return fallback floor or ceiling values when actual prices exceed internal limits or when the feed encounters data instability.

Failing to detect and reject such edge-case values can result in incorrect or exploitable logic paths in smart contracts. This weakness may allow attackers to:

  • Trigger mispriced swaps or asset conversions.
  • Exploit collateralization thresholds.
  • Manipulate auction pricing or tiered reward structures.
  • Influence governance systems based on price weightings.

These issues are especially dangerous during periods of high volatility or partial oracle outages, where fallback values may be automatically returned.

Remediation

To mitigate this risk:

  • Always verify that the oracle-provided price lies within an expected range.
  • Check whether the returned value is a fallback boundary by comparing it against known minPrice/maxPrice values.
  • Monitor and log unusual oracle values for off-chain alerts and incident response.

Example

  • Vulnerable contract 

(int256 price,,,) = AggregatorV3Interface(oracle).latestRoundData();

// Uses price directly without checking for boundary values
uint256 tokenAmount = uint256(price) * userInput;
- Fixed Contract 

(int256 price,,,) = AggregatorV3Interface(oracle).latestRoundData();

// Validate that the price is within trusted bounds
require(price > minPrice && price < maxPrice, "Price out of expected bounds");

uint256 tokenAmount = uint256(price) * userInput;
This ensures that the contract rejects unexpected oracle values that might be returned during errors or manipulation attempts.

References