A vault inherits the risk of everything it integrates. The contract can be flawless and still lose funds because an underlying protocol changed a return value, a reward token behaves unusually, or a strategy's exit path is not viable at the size it has grown to.
Much of our repeat work is exactly this: reviewing each new integration as it is added, so the risk is assessed at the boundary rather than after deployment.
Tell us what you're building. Yield, Farming and Vault Audits is an area we work in constantly.