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Rewards are distributed according to the impact the vulnerability could otherwise cause based on the Impacts in Scope table further below.

Reward Calculation for Critical Level Reports

For critical Blockchain/DLT bugs, the reward is dependent on the ratio between the funds at risk, which includes all affected projects on top of the respective blockchain/DLT, and the market cap according to the average between CoinMarketCap.com and CoinGecko.com calculated at the time the bug report is submitted. However, a minimum reward of USD $50,000 is to be rewarded in order to incentivize security researchers against withholding on a bug report.

This ratio is known as the “risk ratio”, i.e.: Risk Ratio = Funds at Risk / Scroll Market Cap

The reward is then calculated linearly from 0:1 to 1:1, where 1:1 results in a reward of USD $1,000,000. In the event of where the funds at risk are greater than the market cap, the maximum reward remains as the hard cap.

For critical Smart Contract bugs, the reward amount is 10% of the funds directly affected, with a maximum reward amount of USD $1,000,000. The calculation of the amount of funds at risk is based on the time and date the bug report is submitted. However, a minimum reward of USD $50,000 is to be rewarded in order to incentivize security researchers against withholding a bug report.

Reward Calculation for High Level Reports

High smart contract vulnerabilities have a reward amount of 100% of the funds affected, subject to repeatable attacks and feasibility limitations with a maximum cap of USD $50,000.

Repeatable Attack Limitations

In cases of repeatable attacks for blockchain/DLT bugs, only the first attack is considered if the component where the vulnerability exists can be upgraded, paused, or killed. If the attack impacts a component directly holding funds that cannot be upgraded, paused, or killed, the amount of funds at risk will be calculated with the first attack being at 100% of the funds at actual risk. A reduction of 25% from the first amount of the first attack for every 1 hour the attack needs for subsequent attacks from the first attack, rounded down. For avoidance of doubt, if a second attack would happen at 2 hours and then a third at 3 hours, the additional rewards would be counted at 50% and 75% reduction of the reward from the first attack, respectively.

In cases of repeatable attacks for smart contract bugs, only the first attack is considered if the smart contracts where the vulnerability exists can be upgraded, paused, or killed. If the attack impacts a smart contract directly holding funds that cannot be upgraded or paused, the amount of funds at risk will be calculated with the first attack being at 100% of the funds that could be stolen and then a reduction of 25% from the amount of the first attack for every 300 blocks the attack needs for subsequent attacks from the first attack, rounded down. For avoidance of doubt, if a second attack would happen at 600 blocks and then a third at 900 blocks, the additional rewards would be counted at 50% and 75% reduction of the reward from the first attack, respectively.

Restrictions on Security Researcher Eligibility

Security researchers who fall under any of the following are ineligible for a reward

• Current employees, vendors (auditors), partners and contractors are not eligible to participate in the bug bounty program

Previous Audits

Scroll has provided these completed audit review reports for reference. Any unfixed vulnerability mentioned in these reports are not eligible for a reward.

• Blockchain
  • zkTrie (Trail of Bits)
  • L2geth (Trail of Bits)
  • L2geth diff (Trail of Bits)
  • ZkEVM EIP-4844 Blob Support
• Smart Contracts
  • OpenZeppelin Phase 1
  • OpenZeppelin Phase 2
  • OpenZeppelin GasSwap, Multiple Verifier, Wrapped Ether and Diff
  • OpenZeppelin ScrollOwner and Rate Limiter
  • OpenZeppelin USDC Gateway
  • OpenZeppelin contract diff
  • OpenZeppelin Bridge Gas Optimizations
  • OpenZeppelin ZKTrie Verifier
  • OpenZeppelin EIP-4844
  • OpenZeppelin Batch Token Bridge
  • Zellic v1
  • Zellic v2
  • Scroll Lido Gateway - Zellic
  • ScrollOwner and Rate Limiter Audit

Feasibility Limitations

At Immunefi, we sometimes receive reports that are valid (the bug and attack vector are real) and cite assets and impacts that are in scope, but there may be obstacles or barriers to executing the attack in the real world. In other words, there is a question about how feasible the attack really is. If it’s obviously feasible, then it seems there are no questions about severity or payout amount. But if the bug report is less feasible, or not really feasible at all, suddenly questions arise.

Therefore, Immunefi has developed a set of feasibility limitation standards which by default states what a Projects should or should not cite when downgrading a bug report’s impact, severity, and/or payout amount. These standards are continuously being developed and updated with help of the community and encompasses fair guidelines where the project clearly commits, and the security researcher can be assured that the project cannot arbitrarily downgrade the program based on theoretical counter measures, such as a chain rollback.

Proof of Concept (PoC) Requirements

A PoC is required for the following severity levels:

• Blockchain/DLT: Critical
• Blockchain/DLT: High
• Smart Contracts: Critical
• Smart Contracts: High
• Smart Contracts: Medium

All PoCs submitted must comply with the Immunefi-wide PoC Guidelines and Rules. Bug report submissions without a PoC when a PoC is required will not be provided with a reward.

Reward Payment Terms

Payouts are handled by the Scroll team directly and are denominated in USD. However, payments are done in USDC.