What does it mean when one of the most security-conscious teams in DeFi loses $121M to a vulnerability that passed multiple audits?

It means the security model is broken. 🧵 2/ Balancer did everything right: comprehensive audits, security-first culture, experienced team.

They still lost $121M to a rounding error that required 100 billion simulation iterations to find.

That's not a Balancer problem. That's an industry problem.

🧵 Most security reviews focus on what's there.The code that exists.

The functions that run.

The checks that execute. But 80% of exploits come from what's missing.The check that should exist but doesn't.

The validation that was assumed but never coded.

The safeguard the design required but implementation skipped. 2/ Auditors read code line by line.
They check for:

Reentrancy guards
Access control modifiers
Input validation
Math overflow protection

All critical. All necessary.
But they miss the silent killers: the protections that should be there but aren't.