External Call Vulnerability

Definition ∞ An external call vulnerability is a security flaw in a smart contract that arises from its interaction with other contracts or external addresses. This type of weakness occurs when a smart contract makes a call to another contract or an external account without proper validation or safeguards. A malicious external contract could then execute unexpected code or re-enter the calling contract multiple times, leading to unintended state changes or asset drainage. Such vulnerabilities can be exploited to bypass security checks or siphon funds from the affected contract.
Context ∞ Reports of external call vulnerabilities frequently appear in blockchain security audits and crypto news, emphasizing the importance of secure smart contract development practices. Developers employ design patterns like checks-effects-interactions and reentrancy guards to prevent such exploits. The ongoing focus is on comprehensive static analysis tools and formal verification methods to identify and eliminate these critical flaws before deployment.

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→Input Validation Flaw

→Asset Manager Risk

→User Asset Theft

Arcadia Finance Drained $3.6m via Rebalancer Contract Input Validation Flaw

Unchecked `swapData` in the Rebalancer contract enabled a malicious router injection, granting unauthorized access to user liquidity provider assets.

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→Protocol Insolvency Risk

→Multi-Chain Exposure

→Systemic Risk Exposure

Beets Finance Drained $3.8 Million Exploiting Inherited Pool Logic Flaw

A systemic logic flaw in a core liquidity pool standard allowed a derivative protocol to be drained, underscoring critical contagion risk in shared DeFi infrastructure.

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→External Call Vulnerability

→Composability Risk

→Multi-Chain Liquidity Drain

Balancer Stable Pools Drained Exploiting Rounding Logic Flaw across Four Chains

The precision error in Stable Pool math enables batched-swap manipulation, exposing audited multi-chain liquidity to systemic drain risk.

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→Liquidity Pool Drain

→Chain State Manipulation

→Protocol Security Audit

Balancer V2 Pools Drained across Multiple Chains Exploiting Rounding Flaw

A critical rounding error in the Balancer V2 Composable Stable Pool logic allowed an attacker to drain $128 million across seven blockchains.

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→Liquid Staked Ethereum

→Impermanent Loss Risk

→Economic Exploit Vector

Balancer V2 Pools Drained via Multi-Chain Smart Contract Logic Flaw

A critical logic flaw in the Balancer V2 vault architecture allowed batch swap price manipulation, enabling unauthorized, systemic asset draining across six chains.