Arcadia V2 Hack

TOTAL LOST $2.5M
Medium Rebalancer contract reentrancy hack base

Summarize with AI

Affected Chain base Incident surface
Recovered - No recovery reported
All-Time Rank #592 By amount stolen
Auditors 1 Prior security audit

Incident Overview

Leverage farming protocol on base

Incident Report

Protocol / Project Arcadia V2
Date of Incident
Affected Chain(s) base
Attack Technique Rebalancer contract reentrancy hack
Classification Protocol Logic
Primary Source View Post-Mortem

Protocol Information

Protocol Type Liquidity manager
Smart Contract Language Solidity
Official Website arcadia.finance
Protocol Twitter/X @ArcadiaFi

What the Attacker Needed to Succeed

Understanding the prerequisites for this type of attack helps auditors identify protocols that are most at risk and helps developers build better defenses.

Technical Knowledge Deep understanding of rebalancer contract reentrancy hack and Solidity and EVM internals
Capital Required Seed capital to cover gas and initial position setup
On-Chain Access Ability to interact with base smart contracts and deploy a custom exploit contract
Protocol Analysis Identification of the exploitable vulnerability in Arcadia V2's contract logic - root cause: protocol logic
Execution Speed Precise transaction ordering and timing to exploit the vulnerability within a single atomic block
Obfuscation Plan A strategy to launder and move stolen funds - typically through mixers, cross-chain bridges, or decentralized DEX swaps to resist tracing

What Auditors Should Check

Could this have been caught in audit? Yes — skilled auditors routinely flag Rebalancer contract reentrancy hack vulnerabilities in code review
Audited by Audit Report 1 — still lost $2.5M. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to Arcadia V2, these are the critical security checks that could have prevented this incident (July 2025).

  • Verify all logic paths related to Rebalancer contract reentrancy hack are guarded by proper access controls and input validation - see the Reentrancy attack class for patterns
  • Check that all state-changing functions follow the Checks-Effects-Interactions (CEI) pattern to prevent reentrancy and logic ordering bugs
  • Review privileged functions (owner, admin, governance) for potential abuse vectors - centralization risks should be documented and bounded with timelocks or multi-sigs

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Security Audit History

Related Attack Classes

The technique used in this hack maps to these vulnerability classes in our security curriculum:

See all Reentrancy examples →

Sources & References

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