Reentrancy Variant

Definition ∞ A reentrancy variant is a specific type of smart contract vulnerability where an external call allows a malicious contract to repeatedly call back into the original contract before its state is updated. This exploit permits an attacker to drain funds or manipulate logic by executing multiple withdrawals or actions within a single transaction, bypassing safeguards designed for single interactions. Different variants arise from subtle coding errors or unexpected interactions between complex contract functions. Understanding these variations is crucial for developing secure decentralized applications.
Context ∞ Reentrancy variants remain a significant and evolving threat in smart contract security, frequently appearing in reports of DeFi hacks. The situation requires continuous vigilance from developers to identify and patch new manifestations of this vulnerability. A critical future development involves the widespread adoption of secure coding patterns, static analysis tools, and formal verification methods specifically designed to prevent all known and emerging reentrancy attack vectors.