What Is the Concept of “Reentrancy” and How Does It Relate to Flash Loan Exploits?

Reentrancy is a vulnerability where an external contract call recursively calls back into the original contract before the first execution is complete, allowing the attacker to drain funds. While not directly a price feed attack, a flash loan can be used to acquire the necessary capital or governance tokens to set up and execute a reentrancy attack on a vulnerable protocol function, often in conjunction with other exploits.