Audit name:
[SCA] Europeum | Bootstrap | Jul2026
Date:
Aug 12, 2026
Table of Content
Introduction
We express our gratitude to the Europeum team for the collaborative engagement that enabled the execution of this Smart Contract Security Assessment.
Europeum operates and scales Europe’s sovereign digital trust infrastructure, enabling secure, transparent, and interoperable services across the public and private sectors. The Bootstrap package provides shared Solidity utilities used by other Europeum smart contracts.
Document | |
|---|---|
| Name | Smart Contract Code Review and Security Analysis Report of Bootstrap for Europeum |
| Audited By | Seher Saylik |
| Approved By | Kerem Solmaz |
| Website | https://europeum.eu/→ |
| Changelog | 30/07/2026 - Preliminary Report |
| 31/08/2026 - Second Report | |
| 21/09/2026 - Updated Final Report | |
| Platform | Private Chain |
| Language | Solidity |
| Tags | Proxy, Upgradable |
| Methodology | https://docs.hacken.io/methodologies/smart-contracts→ |
Document
- Name
- Smart Contract Code Review and Security Analysis Report of Bootstrap for Europeum
- Audited By
- Seher Saylik
- Approved By
- Kerem Solmaz
- Website
- https://europeum.eu/→
- Changelog
- 30/07/2026 - Preliminary Report
- 31/08/2026 - Second Report
- 21/09/2026 - Updated Final Report
- Platform
- Private Chain
- Language
- Solidity
- Tags
- Proxy, Upgradable
Review Scope | |
|---|---|
| Repository | https://gitlab.com/europeum/public/core/-/tree/main/contracts/bootstrap→ |
| Commit | 89bb63b |
| Retest | d1535ba |
| Updated Final Commit | f8a252b |
| StringManip address | 0xF2858bee9Aa207187C0f9c30CF3b0F74431ac050→ |
Review Scope
- Commit
- 89bb63b
- Retest
- d1535ba
- Updated Final Commit
- f8a252b
- StringManip address
- 0xF2858bee9Aa207187C0f9c30CF3b0F74431ac050→
Audit Summary
The system users should acknowledge all the risks summed up in the risks section of the report
Documentation quality
Functional requirements are partially documented through inline comments and NatSpec.
Technical description is provided.
Code quality
The code is generally simple and reuses OpenZeppelin components. However, identical
Paginationimplementations are duplicated across several packages, andStringManipis only a thin wrapper around OpenZeppelin’sStrings.toHexString().The development environment is configured.
Test coverage
Code coverage of the project is 0% (branch coverage) as no tests were provided.
System Overview
Europeum Core Services Bootstrap provides shared utility contracts and libraries used by other contracts in the system:
ImplementationInitSelector — an abstract ERC-165 contract that allows upgradeable implementations to report the selector of their initialization function. ProxyFactory uses this information when preparing initialization data for new beacon proxies.
Pagination — a library that calculates pagination parameters and returns selected items from string[], bytes32[], uint256, bytes[], and address[] collections.
StringManip — a library that converts an Ethereum address into its hexadecimal string representation. It is used by the Timestamp system to represent account addresses as owner identifiers.
Privileged Roles
The contracts in scope do not define privileged roles or access-control functions.
Potential Risks
Because callers do not limit page, a very large out-of-range value can overflow the cursor calculation and make the affected pagination getter revert with panic 0x11 instead of returning an empty page.
Because Pagination does not enforce upper bounds on pageSize, a caller that forgets to cap this value may allocate a very large memory array and cause the call to fail with an opaque out-of-memory panic.
Findings
Code ― | Title | Status | Severity | |
|---|---|---|---|---|
| F-2026-1872 | Pagination Helper Returns prev and next in Reversed Order | fixed | Observation | |
| F-2026-1911 | [DualDefense] - ERC-165 Mixin Shadows IAccessControl Interface Support | accepted | Observation |
Appendix 1. Definitions
Severities
When auditing smart contracts, Hacken is using a risk-based approach that considers Likelihood, Impact, Exploitability and Complexity metrics to evaluate findings and score severities.
Reference on how risk scoring is done is available through the repository in our Github organization:
Severity | Description |
|---|---|
Critical | Critical vulnerabilities are usually straightforward to exploit and can lead to the loss of user funds or contract state manipulation. |
High | High vulnerabilities are usually harder to exploit, requiring specific conditions, or have a more limited scope, but can still lead to the loss of user funds or contract state manipulation. |
Medium | Medium vulnerabilities are usually limited to state manipulations and, in most cases, cannot lead to asset loss. Contradictions and requirements violations. Major deviations from best practices are also in this category. |
Low | Major deviations from best practices or major Gas inefficiency. These issues will not have a significant impact on code execution. |
Severity
- Critical
Description
- Critical vulnerabilities are usually straightforward to exploit and can lead to the loss of user funds or contract state manipulation.
Severity
- High
Description
- High vulnerabilities are usually harder to exploit, requiring specific conditions, or have a more limited scope, but can still lead to the loss of user funds or contract state manipulation.
Severity
- Medium
Description
- Medium vulnerabilities are usually limited to state manipulations and, in most cases, cannot lead to asset loss. Contradictions and requirements violations. Major deviations from best practices are also in this category.
Severity
- Low
Description
- Major deviations from best practices or major Gas inefficiency. These issues will not have a significant impact on code execution.
Potential Risks
The "Potential Risks" section identifies issues that are not direct security vulnerabilities but could still affect the project’s performance, reliability, or user trust. These risks arise from design choices, architectural decisions, or operational practices that, while not immediately exploitable, may lead to problems under certain conditions. Additionally, potential risks can impact the quality of the audit itself, as they may involve external factors or components beyond the scope of the audit, leading to incomplete assessments or oversight of key areas. This section aims to provide a broader perspective on factors that could affect the project's long-term security, functionality, and the comprehensiveness of the audit findings.
Appendix 2. Scope
The scope of the project includes the following smart contracts from the provided repository:
Scope Details | |
|---|---|
| Repository | https://gitlab.com/europeum/public/core/-/tree/main/contracts/bootstrap→ |
| Commit | 89bb63b74e88c7e3b1602f4801d682e634b6a521 |
| Second Commit | d1535bacb0ee03fc987339c58324b34c3db14687 |
| Updated Final Commit | f8a252b4695954d2e5dff6ce3b868a289e9c6645 |
| Whitepaper | N/A |
| Requirements | NatSpec |
| Technical Requirements | N/A |
Scope Details
- Commit
- 89bb63b74e88c7e3b1602f4801d682e634b6a521
- Second Commit
- d1535bacb0ee03fc987339c58324b34c3db14687
- Updated Final Commit
- f8a252b4695954d2e5dff6ce3b868a289e9c6645
- Whitepaper
- N/A
- Requirements
- NatSpec
- Technical Requirements
- N/A
Assets in Scope
Appendix 3. Additional Valuables
Additional Recommendations
The smart contracts in the scope of this audit could benefit from the introduction of automatic emergency actions for critical activities, such as unauthorized operations like ownership changes or proxy upgrades, as well as unexpected fund manipulations, including large withdrawals or minting events. Adding such mechanisms would enable the protocol to react automatically to unusual activity, ensuring that the contract remains secure and functions as intended.
To improve functionality, these emergency actions could be designed to trigger under specific conditions, such as:
Detecting changes to ownership or critical permissions.
Monitoring large or unexpected transactions and minting events.
Pausing operations when irregularities are identified.
These enhancements would provide an added layer of security, making the contract more robust and better equipped to handle unexpected situations while maintaining smooth operations.
Frameworks and Methodologies
This security assessment was conducted in alignment with recognised penetration testing standards, methodologies and guidelines, including the NIST SP 800-115 – Technical Guide to Information Security Testing and Assessment →, and the Penetration Testing Execution Standard (PTES) →, These assets provide a structured foundation for planning, executing, and documenting technical evaluations such as vulnerability assessments, exploitation activities, and security code reviews. Hacken’s internal penetration testing methodology extends these principles to Web2 and Web3 environments to ensure consistency, repeatability, and verifiable outcomes.