What Security Vulnerability Is Associated with “Reentrancy” in Smart Contracts?

Reentrancy is a critical vulnerability where an external contract call can recursively call back into the original contract before the first execution is complete. This allows the attacker to repeatedly drain funds from the contract.

The most famous example is the DAO hack, which exploited this flaw.

How Did the DAO Hack Use a Reentrancy Vulnerability?
What Is a Common Vulnerability Found in Smart Contract Code?
What Was “The DAO Hack” and What Were Its Consequences for Ethereum?
What Are the Most Common Smart Contract Vulnerabilities Exploited by State-Sponsored Attackers?
What Are the Differences between Single-Function and Cross-Function Reentrancy Attacks?
Could Modern DeFi Security Tools Have Prevented the DAO Hack?
Why Must State Updates Occur before External Calls?
How Did the DAO Hack Relate to Integer Overflow?

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