DeFiPunk'd

Arbitrum Bridge

Canonical Bridge

TVL $3.1B
Type Canonical Bridge
Chain Ethereum
View on DeFiLlama ↗
Control criteria
Upgradeability Upgradeable Bug bounty Governance forum forum.arbitrum.foundation Docs docs.arbitrum.io
About

Arbitrum Bridge is the canonical bridge for transferring ETH and ERC-20 tokens between Ethereum (L1) and Arbitrum One/Nova (L2 optimistic rollups). Users deposit to L2 near-instantly by locking assets in L1 gateway contracts; withdrawals from L2 to L1 require initiating an outbound transfer on Arbitrum, waiting for assertion posting (~1 hour), then waiting through a 7-day fraud-proof challenge window before finalizing the claim on Ethereum via the Outbox contract. The bridge uses a gateway router pattern to support custom token bridges and is governed by the Arbitrum DAO via ARB token votes and a 12-member elected Security Council with emergency upgrade/intervention powers.

Risk analysis

One card per dimension, sorted by severity. Only Verifiability and Autonomy carry automated signals in Phase 0. See methodology for scope.

Audit a dimension yourself · DEFI@home Contribute an LLM-run assessment — any model, any dimension. Three agreeing runs merge automatically into the public record.

DEFI@home is a distributed audit network modeled on SETI@home: instead of CPU cycles, it crowdsources LLM reasoning. Paste a slice prompt into Claude, ChatGPT, Gemini, or any browsing-capable model, and submit the JSON output as a pull request. The quorum bot merges it once ≥3 independent runs (from different models) reach the same grade — no single model, and no single contributor, can move the needle alone. How it works →

  • Address discovery 11 addresses on file · 1 run Submit run ↗
  • Verifiability Unverified Submit run ↗
  • Control Unverified Submit run ↗
  • Ability to exit 1/3 submitted Submit run ↗
  • Autonomy Unverified Submit run ↗
  • Open Access Unverified Submit run ↗
  • Audit all 5 dimensions · one prompt Submit run ↗
  1. Verifiability tentative
    Open source + 4 audits

    Protocol publishes a GitHub repository and has at least one audit on record. This is a coarse Phase-0 signal only: auditor reputation, scope, and post-audit review coverage are not yet weighted.

    Run your own prompt Submit run ↗
  2. Ability to exit 1/3 model submitted
    Permissionless withdrawal initiation from L2, but 7-day challenge period and Security Council can freeze L1 bridge contracts via emergency upgrade authority
    Tentative grades
    • claude-sonnet-4-5 (autorun) orange

    No quorum yet — verdict and steelman hidden until ≥3 models agree.

    Evidence (7)
    E1
    Primary user exit functions: finalizeInboundTransfer (L1ERC20Gateway, L1GatewayRouter) for claiming L2→L1 withdrawals on Ethereum after challenge period; outboundTransfer (L2 gateway contracts) to initiate withdrawals from Arbitrum L2. No pause guards visible in the L1 gateway/router ABIs.
    E2
    The L1 Bridge (0x8315177aB297bA92A06054cE80a67Ed4DBd7ed3a), L1GatewayRouter (0x72Ce9c846789fdB6fC1f34aC4AD25Dd9ef7031ef), and L1ERC20Gateway (0xa3A7B6F88361F48403514059F1F16C8E78d60EeC) ABIs show no whenNotPaused or _checkResumed modifiers on finalizeInboundTransfer. Withdrawal initiation on L2 is permissionless. Claims of finalized withdrawals on L1 are not directly pause-gated at the function level.
    E3
    No explicit pause role found in the examined L1 bridge contracts. However, the L1GatewayRouter owner() returns 0x3ffFbAdAF827559da092217e474760E2b2c3CeDd (Arbitrum Foundation Upgrade Executor). All three gateway/router contracts are TransparentUpgradeableProxy patterns with upgradeTo/upgradeToAndCall functions, allowing the owner to replace implementation logic. The Upgrade Executor is controlled by the Security Council (9-of-12 multisig for emergency actions) and the L1 Timelock (governed by ARB token vote).
    E4
    The Security Council is a 12-member elected multisig that can execute emergency actions with 9-of-12 approval. Emergency actions can be executed immediately without prior DAO vote and without an explicit time cap in the constitution. In April 2026, the Security Council froze 30,766 ETH on Arbitrum One via emergency action in response to the Kelp DAO exploit, demonstrating the ability to intervene in user funds on the L2 chain and potentially on bridge contracts via upgrade.
    E5
    Arbitrum One withdrawals follow an optimistic rollup design: users initiate withdrawal on L2 permissionlessly; assertions are posted to L1 within ~1 hour; a challenge period of 45,818 L1 blocks (~6.5–7 days assuming 12-second blocks) must elapse before the withdrawal can be finalized on L1 via the Outbox executeTransaction function. This is not a daily cap but a fixed delay for fraud-proof verification. The queue itself is not admin-pausable at the function level but the bridge is upgradeable.
    E6
    Arbitrum documentation describes a force-inclusion mechanism: users can send transactions directly to the L1 Delayed Inbox contract to bypass a non-responsive sequencer after 24 hours, ensuring censorship resistance for initiating withdrawals even if the sequencer is down. No explicit emergency-exit function for adversarial admin scenarios on the L1 bridge contracts themselves.
    E7
    Withdrawal initiation on L2 is done via standard contract calls (outboundTransfer on gateway contracts); finalization on L1 requires calling the Outbox executeTransaction with a Merkle proof. Both are directly callable on-chain via block explorers or wallets without frontend dependency. The bridge interface simplifies the process but is not required.
    Why is this slice uncertain?
    • only 1 of 3 model submissions on record — quorum requires ≥3 agreeing models

    A fresh independent run can establish (or overturn) a verdict.

    Run your own prompt Submit run ↗
    Sources claude-sonnet-4-5 (autorun) no url View raw submissions ↗
  3. Autonomy tentative
    External message validators reduce autonomy

    Bridges rely on an external validator set, guardian signatures, or light-client proofs — a category-level autonomy risk independent of any specific implementation.

    Run your own prompt Submit run ↗
2 dimensions not yet assessed (Control, Open Access)
  1. Control unknown Unverified
    Not yet assessed

    Who holds admin privileges, how contracts can be upgraded, and how quickly. No automated heuristic grades this at Phase 0; a real assessment arrives when onchain discovery reads roles, owners, and timelocks.

    No model has graded this dimension yet. Run the slice prompt through any LLM and submit the JSON — once ≥3 independent runs agree, the quorum bot merges the verdict here.

    Submit run ↗
  2. Open Access unknown Unverified
    Not yet assessed

    Whether the protocol depends on privileged operators, whitelists, geo-restrictions, or off-chain infrastructure. This is not a signal DeFiLlama carries in a usable form; crawler-based detection lands in a later phase.

    No model has graded this dimension yet. Run the slice prompt through any LLM and submit the JSON — once ≥3 independent runs agree, the quorum bot merges the verdict here.

    Submit run ↗

Stage

Preview of the Phase-3 maturity framework. DeFiPunk'd will adopt DeFiScan v2's stages verbatim; the section is rendered below in its intended shape so the structure is visible today.

Arbitrum Bridge has not yet been assessed under the DeFiScan v2 stage framework.
The walkaway test is the central criterion. Once stages land, protocols reach Stage 1 only if users can exit in the presence of malicious operators even when the emergency council disappears.
Scope of assessment
Stages are assessed per-protocol against DeFiScan v2's criteria: governance structure, upgradeability path, timelock durations, emergency-council scope, and the walkaway test. The analysis depends on onchain discovery (roles, owners, timelocks) and deeper review of deployed contracts — neither of which DeFiPunk'd automates at Phase 0.
Stage 0 requirements pending
Governance is largely off-chain, contracts are upgradeable with short or no timelock, and the protocol depends on a multisig or team with full discretion. At Phase 0 DeFiPunk'd does not automatically evaluate these; the assessment lands with crawler-based onchain discovery.
Stage 1 requirements pending
Users can exit or opt out on their own terms even if the team disappears. Upgrades run through a meaningful timelock with an emergency security council clearly scoped. The walkaway test is the headline criterion.
Stage 2 requirements pending
Protocol is fully permissionless and immutable, or upgrades require a supermajority of token holders with a long timelock and no emergency override. This is the terminal stage of the DeFiScan v2 framework.
Learn more about DeFiScan v2 stages →
Stages are an opinionated assessment of maturity, not a rating of security or safety. A protocol can sit at Stage 2 and still carry substantial technical or economic risk; the framework exists to incentivize decentralization, not to rank protocols.

Contract surface

Every contract in scope for this protocol — pooled from DeFiLlama's TVL adapter (mechanical) and DEFI@home discovery submissions (LLM-curated). Verified-source flags come from Etherscan + Sourcify; owner / multisig metadata is read on-chain when available. Reviewer audit context, not a slice score. A lending protocol's adapter set will list third-party collateral tokens alongside its own contracts; attribution is the grader's job.

  • 10addresses
  • 4verified source
  • 3proxies
  • 0of 1 owners are Safes

TVL adapter pinned at 683d369. Sourcecode fetched 2026-05-06. Control fetched 2026-05-07.

ethereumL1Escrow0xa10c…9400TVL
ethereumTransparentUpgradeableProxy0xcee2…180dTVLproxy0x3fff…cedd
ethereumTransparentUpgradeableProxy0x8315…ed3aTVL + discproxybridge
ethereumTransparentUpgradeableProxy0xa3a7…0eecTVL + discproxybridge
Ethereumbridge (legacy)0x011b…d515discoverybridge
Ethereumbridge (variant Bridge 2)0x2f06…cb16discoverybridge
Ethereumgateway (L1DaiGateway)0xd3b5…3011discoverybridge
Ethereuminbox (Delayed Inbox)0x4dbd…ab3fdiscoverybridge
Ethereumother (Bridge Utils)0x84ef…18ecdiscoverybridge
Ethereumrouter (L1GatewayRouter)0x72ce…31efdiscoveryrouter

Protocol Info

Security

[:] Source: DEFI@home quorum
Audits
4 audits
Bug bounty
unknown
Security contact
unknown

Technical

[:] Source: DEFI@home quorum
Voting token
ARB Arbitrum One: 0x912CE59144191C1204E64559FE8253a0e49E6548
Upgradeability
Upgradeable

Provenance

[defillama] Source: DeFiLlama
Review status
listed
Updated
2026-06-01 11:27 UTC