Earn V2 Core - Standard Implementation - Blueprint Finance

1. Introduction

Blueprint Finance engaged Halborn to perform a security assessment of their smart contracts from September 3rd, 2025 to September 16th, 2025. The assessment scope was limited to the smart contracts provided to Halborn. Commit hashes and additional details are available in the Scope section of this report.

The Blueprint Finance codebase in scope consists of smart contracts implementing a modular, upgradeable ERC4626 vault system with strategy allocation, hooks, role-based access control, and factory-managed proxy deployment.

2. Assessment Summary

Halborn was allocated 10 days for this engagement and assigned 1 full-time security engineer to conduct a comprehensive review of the smart contracts within scope. The engineer is an expert in blockchain and smart contract security, with advanced skills in penetration testing and smart contract exploitation, as well as extensive knowledge of multiple blockchain protocols.

The objectives of this assessment are to:

• Identify potential security vulnerabilities within the smart contracts.

• Verify that the smart contract functionality operates as intended.

In summary, Halborn identified several areas for improvement to reduce the likelihood and impact of security risks. These were partially addressed by the Blueprint Finance team. The primary recommendations were:

• Integrate the performanceFeeHighWaterMark variable into the performance fee logic.

• Require that allocated == 0 before allowing a strategy to be removed, regardless of its status. Remove the exception for Halted status.

• Update allocation logic to compare the vault's asset balance before and after the call, and use the actual delta for allocated updates.

• Require that a strategy is not present in deallocationOrder before allowing its removal, regardless of its status. Alternatively, automatically remove the strategy from deallocationOrder as part of the removal process to ensure consistency.

3. Test Approach and Methodology

Halborn conducted a combination of manual code review and automated security testing to balance efficiency, timeliness, practicality, and accuracy within the scope of this assessment. While manual testing is crucial for identifying flaws in logic, processes, and implementation, automated testing enhances coverage of smart contracts and quickly detects deviations from established security best practices.

The following phases and associated tools were employed throughout the term of the assessment:

• Research into the platform's architecture, purpose and use.

• Manual code review and walkthrough of smart contracts to identify any logical issues.

• Comprehensive assessment of the safety and usage of critical Solidity variables and functions within scope that could lead to arithmetic-related vulnerabilities.

• Local testing using custom scripts (Foundry).

• Fork testing against main networks (Foundry).

• Static security analysis of scoped contracts, and imported functions (Slither).