Home / Crypto / Academy / DeFi and yield

The DeFi risk stack: every layer that can fail

DeFi failures are almost never a single thing breaking. They are one thing breaking and six protocols discovering they depended on it.

MODULE 60 OF 64 LEVEL 7: DEFI AND YIELD 14 MIN

The stack, from the bottom up

Every DeFi position sits on a tower of dependencies. Money can be lost at any level, and a failure at a lower level cannot be avoided by good decisions at a higher one.

Each layer, and how it actually fails

1. The chain

Halts, reorgs, censorship

If the chain stops producing blocks, you cannot exit any position on it. This has happened to major chains. Liquidations cannot process and neither can your withdrawal.

2. The bridge

The most exploited layer in crypto

If your assets arrived cross chain, they are usually claims backed by a bridge contract. Bridge exploits have produced some of the largest single losses in the industry, and the wrapped asset becomes worthless the moment the backing is gone.

3. The oracle

Manipulation and lag

Protocols need prices and cannot see them natively. A manipulated or stale feed causes wrong liquidations, wrong borrowing limits, and has repeatedly enabled attackers to drain protocols that were otherwise sound.

4. The contract

Bugs, including in audited code

Rounding errors, reentrancy, access control mistakes. Balancer lost over 100 million dollars in 2025 to a rounding direction error after five years and multiple audits.

5. Governance

Slow rug, or capture

Token holders can vote to change fees, alter collateral parameters, or in the worst designs move treasury assets. Concentrated voting power is an attack vector that requires no exploit at all.

6. Admin keys

The fastest failure

Upgradeable contracts mean whoever holds the key can replace the logic. A single wallet holding that key is not decentralised finance in any meaningful sense.

7. The asset itself

Depeg or collapse

A stablecoin that stops being stable, or a collateral token that falls faster than liquidations can process. Everything above assumes the asset holds value.

8. You

Statistically the most likely

Wrong address, wrong network, a malicious approval, a phishing site. More individual money is lost here than to all protocol exploits combined.

Composability: why one failure becomes many

DeFi protocols build on each other freely. A yield vault deposits into a lending market, which accepts a liquid staking token as collateral, which is priced by an oracle, on a chain secured by a bridge.

That composability is genuinely powerful and it means each protocol inherits every dependency below it. When one link breaks, everything built on it discovers the exposure simultaneously, usually within minutes and usually to the surprise of the people who built the upper layers.

A stablecoin used widely as collateral loses its peg.
Lending markets holding it mark down collateral values, so positions become undercollateralised.
Liquidations fire across multiple protocols at once, selling collateral into a falling market.
Yield vaults holding those positions take losses their depositors never modelled.
Liquidity providers in pools containing the asset are left holding almost entirely the broken one.
A protocol that did nothing wrong is insolvent because it accepted the wrong collateral.

This is the pattern behind almost every large DeFi loss event. The lesson is not that DeFi is unusable. It is that the risk of a position is the sum of every dependency beneath it, and that sum is rarely disclosed on the page advertising the yield.

Assessing a protocol before depositing

How long has it held real money? Time under attack is the single strongest signal available. Three years holding hundreds of millions beats any audit report.
Who can change it, and how fast? Renounced, timelocked multisig, or one wallet. If there is a timelock, how long, and is there a public alert if it is used?
What oracle does it use and what happens if it fails? Good protocols document this. If you cannot find the answer, that is the answer.
What is the yield actually paid from? Real fees from real usage, or newly minted tokens. If it is emissions, you are being paid in dilution.
What does it depend on? List every protocol underneath. If the list is long or you cannot complete it, size accordingly.
What happened in the last crash? Protocols that operated correctly through a severe event have demonstrated something no audit can.
Can you exit quickly? Lock ups, withdrawal queues and thin exit liquidity all matter far more in stress than in calm.

The yield question, asked properly

There is no yield without a source. Before depositing, name it. Trading fees from real volume, borrowing interest from real borrowers, staking rewards from a protocol, or newly minted tokens. Those are essentially the options.

If none of those explains the number, the yield is being paid from deposits, and the arithmetic of that is fixed. High yield is not automatically fraudulent, and an unexplained high yield very often is.

Sizing for a layer you cannot evaluate

You will not fully evaluate every dependency, and nobody does. The professional response is to size the position so that a total loss at any layer is acceptable, and to treat each additional layer as a reason to reduce size rather than a reason to increase yield expectations.

BEFORE YOU MOVE ON

I can name the eight layers where a DeFi position can fail I know bridges are the most exploited layer I understand why an oracle failure drains an otherwise sound protocol I can explain how composability chains one failure into many I check how long a protocol has held real money I can name the source of any yield before depositing I size positions assuming a total loss at any layer

Common questions

What are the main risks in DeFi?

Eight layers: the chain, the bridge, the oracle, the contract, governance, admin keys, the underlying asset, and user error. Bridges have produced the largest losses and user error accounts for the most individual losses.

What is composability risk?

DeFi protocols build on each other, so each inherits every dependency beneath it. When one link fails, every protocol above it discovers the exposure at the same time, which is the pattern behind almost every large DeFi loss event.

How do I know if a DeFi yield is real?

Name its source: trading fees, borrowing interest, staking rewards, or newly minted tokens. If none of those explains the number, the yield is being paid from deposits.

Risk warning: crypto is highly volatile and largely unregulated. You can lose everything you put in. Nothing here is financial, investment or tax advice.

← PREVIOUS

Liquid staking and restaking: yield, derivatives and layered risk

Order types: every one, what it does, and when it hurts you