Cross-Chain Bridge Security Audits
Bridges are the highest-risk infrastructure in crypto. They combine multi-chain logic, off-chain relayers, consensus validation, and massive asset custody into a single attack surface. Bridge exploits account for over $3 billion in losses, more than any other protocol category.
Why Bridges Are the Hardest Audit Target
Cross-chain bridges are architecturally unique. They span multiple blockchains, rely on off-chain infrastructure, and custody assets from every chain they connect. A vulnerability in any layer (smart contracts, relayer logic, validator sets, or message verification) can drain every asset the bridge holds.
The Ronin bridge hack ($625M), Wormhole ($320M), and Nomad ($190M) all followed the same pattern: a single point of failure in the bridge's validation logic that allowed attackers to mint or withdraw assets without legitimate cross-chain messages. And the pattern hasn't aged out: in April 2026, Kelp DAO lost $292M when its LayerZero OFT bridge trusted a single compromised DVN — a verifier configuration failure, not a contract bug. These aren't edge cases. They're the defining exploit category of the past four years.
Our Methodology
Our bridge audit methodology covers the full cross-chain attack surface, not just the smart contracts.
Cross-Chain Architecture Mapping
Map the full bridge system: source chain contracts, destination chain contracts, relayer/validator infrastructure, message formats, and asset custody model.
Message Verification Audit
Review the mechanism that validates cross-chain messages. This is where most bridge exploits originate: forged or replayed messages.
Asset Custody Review
Analyze lock/mint and burn/release mechanisms. Verify that asset accounting is consistent across chains and resistant to manipulation.
Relayer & Validator Security
Evaluate the trust model for off-chain components. Assess validator threshold, key management, and liveness assumptions.
Report & Remediation
Multi-chain findings with cross-chain impact analysis. Re-audit of all fixes.
Vulnerability Classes We Target
These are the vulnerability patterns most relevant to this audit type: the ones that cause real losses.
Message Forgery
Insufficient validation of cross-chain messages allowing attackers to fabricate withdrawal or minting requests.
Replay Attacks
Valid messages replayed across chains or re-submitted to drain additional assets beyond the original transaction.
Validator Compromise
Centralized or insufficient validator sets where compromising a threshold of signers grants full bridge control.
Verifier & DVN Misconfiguration
Single-verifier or low-threshold configurations on messaging layers like LayerZero. Kelp DAO ran 17 routes on a 1-of-1 DVN — one compromised verifier printed $292M of unbacked collateral.
Asset Accounting Mismatches
Inconsistencies between locked and minted assets across chains, enabling unbacked withdrawals.
Relayer Manipulation
Off-chain relay infrastructure that can be censored, delayed, or corrupted to influence bridge state.
Frequently Asked Questions
Related Services
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Rust Audits
Specialist Rust smart contract audits for Solana (Anchor + native), NEAR, CosmWasm, and Substrate. Account validation, CPI safety, PDA, and program-logic review.
L1 Chain Audits
Security audits for Layer 1 blockchains: consensus mechanisms, networking layers, validator logic, and runtime environments reviewed at the protocol level.
Chains We Audit
Bridge Audits tuned to the chains where this work matters most.
Related Research
Kelp DAO's $292M Hack and Aave's $6B Fallout: One Config Parameter Broke DeFi
A 1-of-1 LayerZero DVN let attackers drain 116,500 rsETH ($292M) from Kelp DAO, loop it through Aave V3 for $266M in ETH, and wipe $6B in Aave TVL in 24 hours. No Solidity bug. One config parameter broke DeFi.
exploitsThe $3.2M SquidRouterModule Exploit: How a Public String Drained 86 Safe Wallets
A third-party module named SquidRouterModule drained $3.2M from 86 Gnosis Safe wallets on Ethereum and Base. Full attack chain, the auth flaw, and the lesson.
industryWhat Does a Smart Contract Audit Actually Cost in 2026
Real audit pricing data from 2026. What affects cost, what you should expect to pay, and how to evaluate whether an audit is worth the investment for your protocol.
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