Prepared by:
HALBORN
Last Updated 03/05/2026
Date of Engagement: January 30th, 2026 - February 2nd, 2026
100% of all REPORTED Findings have been addressed
All findings
3
Critical
0
High
0
Medium
0
Low
0
Informational
3
Rally Foundation engaged Halborn to perform a security assessment of their smart contracts from January 30th, 2026 to February 2nd, 2026 . 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 Rally bridge contracts implement a cross-chain message relay system where a trusted backend service submits transaction payloads to a BridgeForwarder, which routes them either locally or through LayerZero V2 to a BridgeReceiver on the destination chain, which decodes and dispatches each message to the appropriate target contract for execution.
Halborn 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 risks, which were completely addressed by the Rally Foundation team. The main recommendations were:
Add error handling to the message receiver so a failing target does not stall delivery.
Reject ETH sent with local calls to prevent funds from being permanently locked.
Fix a mislabeled error message that references the wrong contract name.
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.
Fork testing against main networks.
Static security analysis of scoped contracts, and imported functions (Slither).
| EXPLOITABILITY METRIC () | METRIC VALUE | NUMERICAL VALUE |
|---|---|---|
| Attack Origin (AO) | Arbitrary (AO:A) Specific (AO:S) | 1 0.2 |
| Attack Cost (AC) | Low (AC:L) Medium (AC:M) High (AC:H) | 1 0.67 0.33 |
| Attack Complexity (AX) | Low (AX:L) Medium (AX:M) High (AX:H) | 1 0.67 0.33 |
| IMPACT METRIC () | METRIC VALUE | NUMERICAL VALUE |
|---|---|---|
| Confidentiality (C) | None (C:N) Low (C:L) Medium (C:M) High (C:H) Critical (C:C) | 0 0.25 0.5 0.75 1 |
| Integrity (I) | None (I:N) Low (I:L) Medium (I:M) High (I:H) Critical (I:C) | 0 0.25 0.5 0.75 1 |
| Availability (A) | None (A:N) Low (A:L) Medium (A:M) High (A:H) Critical (A:C) | 0 0.25 0.5 0.75 1 |
| Deposit (D) | None (D:N) Low (D:L) Medium (D:M) High (D:H) Critical (D:C) | 0 0.25 0.5 0.75 1 |
| Yield (Y) | None (Y:N) Low (Y:L) Medium (Y:M) High (Y:H) Critical (Y:C) | 0 0.25 0.5 0.75 1 |
| SEVERITY COEFFICIENT () | COEFFICIENT VALUE | NUMERICAL VALUE |
|---|---|---|
| Reversibility () | None (R:N) Partial (R:P) Full (R:F) | 1 0.5 0.25 |
| Scope () | Changed (S:C) Unchanged (S:U) | 1.25 1 |
| Severity | Score Value Range |
|---|---|
| Critical | 9 - 10 |
| High | 7 - 8.9 |
| Medium | 4.5 - 6.9 |
| Low | 2 - 4.4 |
| Informational | 0 - 1.9 |
Critical
0
High
0
Medium
0
Low
0
Informational
3
| Security analysis | Risk level | Remediation Date |
|---|---|---|
| BridgeReceiver lacks error handling and recovery path for failed message forwarding | Informational | Solved - 02/08/2026 |
| ETH sent during local message delivery is permanently locked with no recovery mechanism | Informational | Solved - 02/08/2026 |
| Incorrect error string in BridgeForwarder local delivery path | Informational | Solved - 02/08/2026 |
//Informational
//Informational
//Informational
Halborn strongly recommends conducting a follow-up assessment of the project either within six months or immediately following any material changes to the codebase, whichever comes first. This approach is crucial for maintaining the project’s integrity and addressing potential vulnerabilities introduced by code modifications.
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Bridge Contracts
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