Uniswap Labs / uniswap-v4

The Uniswap protocol is a peer-to-peer system designed for exchanging cryptocurrencies (ERC-20 Tokens) on the Ethereum blockchain. The protocol is implemented as a set of persistent, non-upgradable smart contracts; designed to prioritize censorship resistance, security, self-custody, and to function without any trusted intermediaries who may selectively restrict access.

Prize distribution and scoring

Total Prize Pool: $2,350,000
Primary Prize Pool: $2,250,000

Formal Verification Prize Pool: $100,000

• The Primary prize pool distribution has 4 possible triggers:

  • If one or more valid Low severity findings are found, the primary pot size is $50,000
  • If one or more valid Medium severity findings are found, the primary pot size is $300,000
  • If one or more valid High severity findings are found, the primary pot size is $1,050,000
  • If one or more valid Critical severity (see below for definition) findings are found, the primary pot size is $2,250,000

• $50,000 of the prize pot reserved for Low Severity findings. These reports are judged based on quality and reviewers are then ranked from 1st to 10th for the purpose of prize allocation.

  • 1st - 3rd: $10,000
  • 4th - 6th: $5,000
  • 7th: $2,500
  • 8th: $1,250
  • 9th - 10th: $625

Note that for Low findings, we want to encourage high-quality non-trivial submissions. Given that the codebase has gone through multiple reviews before, and due to the large number of participants, we’ll be marking any trivial low findings as informational and may not be considered for reward. To reiterate, the above pot is judged on quality alone and not quantity.

• Formal Verification prize Pool:
  • $100k is reserved for the formal verification pool. Full details here

Severity definition:

Please note that the competition has an additional Critical severity, here are the severity definitions and conditions applied on these severities.

The following percentage values used below to calculate loss of funds are based on the assumption that all of Uniswap v3 liquidity is moved to Uniswap v4 Currently the TVL is $1.7B

Critical severity:

• Critical severity is unlocked if a High severity finding results in losses from 50%-100% of the total TVL across all chains.
• Please note there must be sufficient information and undeniable Proof of concept which should be easily verifiable for the loss amount for the finding to be considered Critical with absolutely no ambiguity.

High severity:

• High severity is unlocked if the finding results in losses from 5-50% of the total TVL across all chains.
• Regarding fees:
  • If someone can avoid paying swap fees (LP or protocol) across multiple assets and multiple chains - i.e. not due to a specific chain or specific asset's implementation, would be High severity
  • If someone can steal LP/protocol fees that are not theirs across multiple assets and multiple chains - i.e. not due to a specific chain or specific asset's implementation, would be High severity

Medium severity:

• A DoS that can prevent access to more than 5% of total TVL for more than 1 minute, for less money than the value of the funds in question.

• Individual losses (by stealing, wasting or permanently freezing) impacting at least 1% of individual users, which lose at least 1% of the funds they put in.

Low severity:

• A DoS that can prevent access to more than 1% of TVL for more than 1 minute, for less money than the value of the funds in question.

• Any individual losses of at least 1% of their funds.

Risk Classification Matrix

Severity level	Impact: High	Impact: Medium	Impact: Low
Likelihood: High	Critical/High (Conditional)	High	Medium
Likelihood: Medium	High	Medium	Low
Likelihood: Low	Medium	Low	Informational

1. Impact Assessment

• High: Leads to a loss of a significant portion of assets in the protocol, or significant harm to a majority of users. Core Protocol functionality broken. Permanent locking of funds.
• Medium: Losses to only a subset of users, but still unacceptable. DOS of funds for days or more.
• Low: Losses will be annoying but bearable-applies to things like griefing attacks that can could be easily fixed.

2. Likelihood Assessment

• High: Almost certain to happen, easy to perform, or not easy but highly incentivized.
• Medium: Only conditionally possible or incentivized, but still relatively likely.
• Low: There are rare events but are theoretically possible under certain extreme but realistic market conditions

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• Please note that in case of any ambiguity or categories outside of the above, the Judges+Cantina team will have the final say on the severity of the findings.
• Please read the following description of how to submit a good finding
• Additional information on Severities described in detail on our docs page.
• This competition has a custom scoring mechanism. Please read the Scoring Mechanism section below for details.

Scoring Mechanism

Points

• A Critical Severity finding is worth 20 points.
• A High severity finding is worth 10 points.(Same as the usual scoring mechanism)
• A Medium severity finding is worth 3 points.(Same as the usual scoring mechanism)

Early Submission Incentive

• Uniswap is one of the most important protocols in the ecosystem. To make sure their upcoming V4 launch is completed on schedule, researchers are incentivized to submit Critical/High/Medium severity findings early, ie: as soon as one is found. The first valid submission will be rewarded an additional 20% reward, in comparison to its subsequent duplicates.
• The finding must identify the root cause, highest valid impact and describe the finding with all the necessary details to consider it valid.
• Please note that low quality or vague submissions or submissions that could be subject to interpretations will not be considered for the additional reward.
• The escalation process will not apply for these rewards and there will be no discussion for these rewards. The decision made by the Judges/Uniswap team on these rewards will be final.
• Example: If a finding has 5 duplicates.
  • Using regular each of the duplicates would get $2000 each
  • With the current incentive of 20%. The earliest valid submission gets $2307.72, and the rest of the duplicates get $1923.07 each.

Documentation

• Uniswap-V4 Whitepaper

Scope

• v4-core
  • commit: 18b223c
  • scope:
    • PoolManager.sol and ALL files it relies on

Contract	nsloc
Extsload.sol	64
ERC6909Claims.sol	23
ProtocolFees.sol	103
NoDelegateCall.sol	33
TransientStateLibrary.sol	49
SwapMath.sol	108
UnsafeMath.sol	29
FixedPoint96.sol	10
SafeCast.sol	60
FullMath.sol	117
LPFeeLibrary.sol	79
CurrencyDelta.sol	42
SqrtPriceMath.sol	289
FixedPoint128.sol	8
StateLibrary.sol	346
CurrencyReserves.sol	48
TickMath.sol	230
NonzeroDeltaCount.sol	35
BitMath.sol	49
Pool.sol	606
CustomRevert.sol	97
Hooks.sol	342
ParseBytes.sol	29
ProtocolFeeLibrary.sol	48
Lock.sol	28
TickBitmap.sol	122
LiquidityMath.sol	20
Position.sol	103
PoolManager.sol	385
ERC6909.sol	90
Exttload.sol	40
Currency.sol	117
Slot0.sol	94
BeforeSwapDelta.sol	38
PoolId.sol	17
BalanceDelta.sol	72
PoolKey.sol	22
BipsLibrary.sol	18

• v4-periphery
  • commit: 151b282
  • scope:
    • PositionManager.sol
    • V4Router.sol
    • and ALL files they rely on

Contract Name	nSLOC
PositionManager.sol	435
ReentrancyLock.sol	20
Multicall_v4.sol	25
Notifier.sol	118
UnorderedNonce.sol	31
BaseActionsRouter.sol	74
EIP712_v4.sol	51
PoolInitializer.sol	16
SafeCallback.sol	24
ImmutableState.sol	12
ERC721Permit_v4.sol	108
Permit2Forwarder.sol	32
DeltaResolver.sol	87
StateView.sol	189
SlippageCheck.sol	46
ERC721PermitHash.sol	44
CalldataDecoder.sol	274
Locker.sol	21
ActionConstants.sol	15
PathKey.sol	29
Actions.sol	40
V4Router.sol	176
PositionInfoLibrary.sol	248

• universal-router
  • commit: a81e1ce
  • scope:
    • UniversalRouter.sol
    • and ALL files it relies on.
    • While this whole file can be in scope, much of the code is already on mainnet and has been for nearly 2 years. We would like particular focus on the new/changed code in the following contracts.

Contract Name	nSLOC
UniversalRouter.sol	67
Dispatcher.sol	302
Lock.sol	27
MaxInputAmount.sol	20
Locker.sol	27
MigratorImmutables.sol	22
V4SwapRouter.sol	17
V3ToV4Migrator.sol	19
V3SwapRouter.sol	170

• In the dispatcher contracts the following functions:
  • V4_POSITION_CALL
  • V3_POSITION_MANAGER_CALL
  • V3_POSITION_MANAGER_PERMIT
  • V4_SWAP

Chains

• ethereum mainnet
• arbitrum
• avalanche
• base
• blast
• bnb
• celo
• optimism
• polygon
• zksync
• zora
• Any un-altered OP Stack or Arbitrum Orbit chain

Build Instructions

• v4-core and v4-periphery:

  • forge build
  • forge test –isolate
  • for quick compilation without via-ir, use: FOUNDRY_PROFILE=debug forge build

• universal-router:

  • yarn compile
  • yarn test:all

Out of Scope issues

• Previous security reviews. All reports should also be available within the audits folder of each repository(for v4-periphery please refer link below)
  • v4-core audits
  • v4-periphery audits
  • universal-router audits
• Known Effects of Hooks
• Multi-hop swaps on v3, where a latter hop is on a low liquidity pool, and the user’s slippage requirements are met, can leave intermediate tokens in the router.
• Permit2 calls where the token provided has codesize 0 succeed
• Low liquidity pools can break our invariant of custom accounting in swaps. Namely if the amount available to swap in a pool is less than userAmountSpecified + hookDeltaInSpecified then the hook will still end up with a delta of hookDeltaInSpecified, but the user’s amountSpecified will get altered.
• Malicious tokens can drain all pools that use that token, however they should not be able to reach beyond pools of the same token.
• In v3, a swap’s amountSpecified was positive for exactIn, and negative for exactOut. In v4 it is the opposite: negative for exactIn, and positive for exactOut. Think of it as the delta in the user’s balance.
• Similar to v3, our code assumes that the total supply of any token does not exceed 2^{128} - 1, i.e. type(uint128).max.
• Rebasing tokens do not work directly as liquidity in uniswap v4, only wrapped rebasing tokens should be used. However wrapping can be automated through the use of hooks and the BeforeSwapDelta.
• Admin / Permissioned roles: The owner of the PoolManager can set the protocol fee controller. Setting a malicious protocol fee controller should not be able to prevent initialization of new pools, nor exceed the maximum allowed protocol fee on any pools.
• yield accrued natively on blast would be lost
• 1wei of tokens may be left when removing liquidity from a position in v4
• All security researchers involved with the Uniswap V4 reviews previously are not eligible for the competition

Automated findings generated by LightChaserV3

• v4-core
• v4-periphery
• universal-router