solidity-security

Apply the Checks-Effects-Interactions pattern by updating state before external calls, and add OpenZeppelin's ReentrancyGuard with the nonReentrant modifier. CEI alone does not stop cross-function reentrancy, so use both defenses together.

Never use Uniswap slot0 or reserve ratios as price oracles since they can be manipulated in one transaction. Use a Uniswap V3 TWAP with a 30-minute window or Chainlink feeds with staleness, negative price, and round completeness checks.

A first depositor donates tokens directly to an empty vault to inflate share price, causing later depositors to mint zero shares. OpenZeppelin's virtual offset via _decimalsOffset() makes the attack cost 10^offset times more expensive.

Slither is fast static analysis suited for CI on every PR. Mythril uses symbolic execution to find deep logic bugs but is slower. Foundry fuzzing tests with real EVM execution and should run during development with 10,000+ runs before deployment.

USDT requires resetting allowance to zero before setting a new value, and its approve returns no boolean. Use OpenZeppelin SafeERC20's forceApprove, which handles the reset and non-standard return values automatically.

Never remove, reorder, or insert variables between existing storage slots; only append new ones and use __gap arrays to reserve slots. Include _disableInitializers() in the implementation constructor and protect _authorizeUpgrade with access control.