Is Yield Basis (YB) Safe? Smart Contract Security Analysis

Security Findings

1 Crit1 High1 Med1 Low1 Info

Critical

Critical Emission Calculation Bug

C-01The `_emissions` function, central to the token's supply mechanism, contains a syntax error and a potential logical flaw in the argument passed to `math._wad_exp`. The line `reserve * (10**18 - math._wad_exp(-dt * rate_36 uint256))` is syntactically incorrect (the `uint256` after `rate_36` is misplaced) and `rate_36` is calculated as `max_mint_rate * rate_factor`, where `max_mint_rate` is already scaled by `10**18`. This over-scaling of the `_wad_exp` argument could lead to `_wad_exp` returning 0 prematurely, causing `amount` to be equal to `reserve` (minting the entire reserve in one go), or causing reverts due to extreme input values, effectively bricking the emission mechanism.

IssueThe `_emissions` function, central to the token's supply mechanism, contains a syntax error and a potential logical flaw in the argument passed to `math._wad_exp`. The line `reserve * (10**18 - math._wad_exp(-dt * rate_36 uint256))` is syntactically incorrect (the `uint256` after `rate_36` is misplaced) and `rate_36` is calculated as `max_mint_rate * rate_factor`, where `max_mint_rate` is already scaled by `10**18`. This over-scaling of the `_wad_exp` argument could lead to `_wad_exp` returning 0 prematurely, causing `amount` to be equal to `reserve` (minting the entire reserve in one go), or causing reverts due to extreme input values, effectively bricking the emission mechanism.

FixCorrect the syntax error in the `_emissions` function. Carefully review the scaling of `rate_36` and the expected input for `math._wad_exp` to ensure the emission formula behaves as intended. The argument to `_wad_exp` typically represents a rate per unit time, often requiring division by `10**18` if the rate itself is WAD-scaled.

StatusUnresolved

High

Irreversible Minter Bricking Risk

H-01The `renounce_ownership` function transfers ownership to the zero address, making the contract ownerless. Concurrently, it sets `erc20.is_minter[msg.sender] = False`, revoking the deployer's minting privileges. If the `set_minter` function (which is owner-restricted) is not called by the deployer *before* renouncing ownership to grant minting rights to a designated entity (like a `GaugeController`), the contract will become permanently unable to mint new tokens, rendering its core emission functionality inoperable.

IssueThe `renounce_ownership` function transfers ownership to the zero address, making the contract ownerless. Concurrently, it sets `erc20.is_minter[msg.sender] = False`, revoking the deployer's minting privileges. If the `set_minter` function (which is owner-restricted) is not called by the deployer *before* renouncing ownership to grant minting rights to a designated entity (like a `GaugeController`), the contract will become permanently unable to mint new tokens, rendering its core emission functionality inoperable.

FixEnsure that the `set_minter` function is called by the deployer to authorize the intended minter (e.g., `GaugeController`) *before* `renounce_ownership` is executed. Implement clear deployment and post-deployment procedures to prevent this critical misconfiguration. Consider adding a check in `renounce_ownership` to ensure at least one minter is active before allowing ownership renunciation, or allow a specific role to set minters even after ownership is renounced (though this goes against the…

StatusUnresolved

Medium

Outdated Vyper Version and Libraries

M-01The contract is compiled with Vyper 0.4.3, which is an outdated version of the language. This version may contain known or undiscovered compiler bugs and lacks modern security features and optimizations present in current Vyper releases. Additionally, the `snekmate` libraries used are likely also outdated, potentially introducing further vulnerabilities or non-standard behaviors.

IssueThe contract is compiled with Vyper 0.4.3, which is an outdated version of the language. This version may contain known or undiscovered compiler bugs and lacks modern security features and optimizations present in current Vyper releases. Additionally, the `snekmate` libraries used are likely also outdated, potentially introducing further vulnerabilities or non-standard behaviors.

FixMigrate the contract to a modern, audited Vyper version (e.g., 0.3.x) and update to actively maintained and audited libraries. Thoroughly re-audit the contract after migration to ensure no new issues are introduced and all existing logic remains correct.

StatusUnresolved

Low

Lack of Emergency Pause Mechanism

L-01The contract lacks a mechanism to pause critical functions like `emit` in case of an emergency, such as a discovered vulnerability or an economic exploit. This could leave the protocol vulnerable to rapid exploitation without a way to mitigate ongoing damage.

IssueThe contract lacks a mechanism to pause critical functions like `emit` in case of an emergency, such as a discovered vulnerability or an economic exploit. This could leave the protocol vulnerable to rapid exploitation without a way to mitigate ongoing damage.

FixConsider implementing a pause mechanism for the `emit` function. This mechanism should be controlled by a trusted multi-signature wallet or a governance process, allowing for a temporary halt of emissions in emergencies. Given the ownerless design, this would need to be integrated carefully, perhaps allowing a designated `GaugeController` or a separate governance contract to trigger a pause.

StatusUnresolved

Info

Implicit Trust in Designated Minter

I-01The contract's design, particularly after ownership renunciation, places implicit trust in an external `GaugeController` (or similar designated minter) to manage token emissions responsibly. The `emit` function's `rate_factor` parameter allows the minter to control the percentage of inflation. The security of the token's supply and economic model heavily relies on the designated minter's implementation, its own access controls, and its resistance to manipulation.

IssueThe contract's design, particularly after ownership renunciation, places implicit trust in an external `GaugeController` (or similar designated minter) to manage token emissions responsibly. The `emit` function's `rate_factor` parameter allows the minter to control the percentage of inflation. The security of the token's supply and economic model heavily relies on the designated minter's implementation, its own access controls, and its resistance to manipulation.

FixConduct a thorough audit of the `GaugeController` contract (or any designated minter) that will interact with this `YBToken`. Ensure its access control mechanisms are robust, its logic is sound, and it cannot be manipulated to mint tokens maliciously or in an unintended manner.

StatusUnresolved

Category Ratings

TechnicalMedium5/10

The contract implements a custom ERC-20 token with an exponential emission model. The architecture is straightforward, leveraging `snekmate` libraries for standard ERC-20 and ownership functionalities. However, a critical bug was identified in the `_emissions` calculation (7.2 Code Security), potentially leading to incorrect token minting or system failure. Additionally, the contract uses an outdated Vyper compiler version (7.2 Code Security), which may expose it to known vulnerabilities. Access control (7.3 Access Control) for minting is based on a minter role, which can be irreversibly misconfigured.

GovernanceMedium4/10

The economic model is based on a continuous exponential emission schedule, designed to deplete a fixed `reserve` over time. The `max_mint_rate` and `reserve` are set at deployment, making the core parameters immutable. A critical bug in the emission calculation (7.4 Economic) directly threatens the intended tokenomics. The system relies on a designated minter (e.g., `GaugeController`) to manage the `rate_factor`, which dictates the actual emission rate. The irreversible ownerless state combined with the minter setup (7.5 Governance) presents a high risk of bricking the emission mechanism if not configured precisely during deployment.

UpgradesMedium5/10

The contract is not designed with upgradeability in mind, meaning its logic is immutable once deployed. This eliminates risks associated with upgrade mechanisms (7.7 Upgrades) but also prevents any future bug fixes or feature enhancements without a full redeployment and migration.

Security Checklist

3/5 checks passed

Contract VerifiedPass

Ownership RenouncedPass

No Mint FunctionFail

Liquidity LockedFail

Not a ProxyPass

Holder Composition

86.2% in top 10

4.8% in wallets81.4% in contracts

Effective Concentration37.4%

Share held by contracts — treasury, vesting, bridge or staking — is discounted against share held by wallets when the score is computed: a contract cannot decide to sell the way an anonymous holder can, though it can still be drained or voted to sell. Effective concentration is the figure the risk score is actually calculated from.

Liquidity Depth

$1.22M across 5 pairs

Curve twocrvUSDanalysed$1.19M Uniswap v3WETH$28.3K Uniswap v4USDC$8.4K

The risk score reads depth across every pair. The volume figure and the volume-to-liquidity ratio elsewhere on this page describe only the pair this audit analysed, so the two are not directly comparable.

LP Distribution

Top-1 Unlocked Holder88.0%

Top-3 Unlocked97.6%

Key Addresses

9 addresses

Deployer

0xa39e…c80d

Unlocked LP Held By

0xda21…e12f0x0a44…d0090xf32b…f01b0x6c7f…a1bb0x8d8a…2d6b0x577b…b1cc0x0a83…11b50x0f71…aac4

No privileged address appears among these holders: the unlocked liquidity sits with independent providers, not with the deployer.

What Raised This Score

9 factors

Mintable supply — no cap found, dilution unbounded
Top-10 concentration > 30% (86.2% total → 37.4% effective; 4.8% in EOAs, 81.4% in contracts — moderate)
Liquidity not locked, but no owner/deployer address holds LP — market-depth risk, not rug risk
LP top1 unlocked holder = 88.0% (independent LP — depth risk, pool = 97% of DEX liquidity)
LP top3 unlocked holders = 97.6% (independent LP — depth risk, pool = 97% of DEX liquidity)
1 Critical finding(s) from audit
1 High finding(s) from audit
1 Medium finding(s) from audit
1 Low finding(s) from audit

Each factor is an on-chain fact recorded at the time of this analysis. The score is computed from them by a deterministic function, so the same contract returns the same score for anyone who runs the audit. How scores are computed

Is Yield Basis Safe?

Security Findings

Critical Emission Calculation Bug

Irreversible Minter Bricking Risk

Outdated Vyper Version and Libraries

Lack of Emergency Pause Mechanism

Implicit Trust in Designated Minter

Category Ratings

Security Checklist

Holder Composition

Liquidity Depth

LP Distribution

Key Addresses

What Raised This Score

Related Audits

Would You Like a More Detailed Audit of Yield Basis?