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Vault, Cosmos & EVM Contracts - NUVA

Prepared by:

Halborn Logo

HALBORN

Last Updated 02/10/2026

Date of Engagement: December 9th, 2025 - December 26th, 2025

Summary

100% of all REPORTED Findings have been addressed

All findings

14

Critical

0

High

0

Medium

0

Low

9

Informational

5

Table of Contents

1. Introduction

NUVA Foundation engaged Halborn to conduct a comprehensive security assessment of the Vault Module on Provenance Blockchain beginning on December 9th, 2025, and concluding on December 26th, 2025. The scope of this assessment was limited to the smart contracts and Cosmos-SDK Vault module provided to the Halborn team. Commit hashes, scope boundaries, and additional technical details are documented in the Scope section of this report. '

The Vault Module is a public, permissionless, proof-of-stake blockchain, purpose-built to modernize financial infrastructure. It is more than just a general-purpose ledger; it's an integrated ecosystem designed for finance.

2. Assessment Summary

Halborn assigned a full-time security engineer to perform a comprehensive review of the contracts. The engineer is a blockchain and smart contract and blockchain security expert with extensive experience in penetration testing, vulnerability research, and auditing across multiple blockchain ecosystems.


The purpose of this assessment was to:

    • Identify potential security issues and vulnerabilities within the EVM and Cosmos Vault smart contracts along with the Integration of a specific Cosmos-SDK vault module.

    • Ensure that all contract components function as intended under expected and edge-case conditions.

 

In summary, Halborn identified several areas for improvement to minimize both the likelihood and potential impact of security risks, which were mostly acknowledged by the NUVA Foundation. The primary recommendations included:

    • Reject SwapOut requests where the computed redeemable assets are zero (return a clear “amount too small” error), or treat zero-asset conversions as a recoverable failure in payout processing and refund shares instead of burning.

    • Introduce a separate per-block scan budget that counts skipped paused entries, or move paused-vault jobs out of the due-walk path.

    • Remove the hardcoded uylds.fcc 1:1 path and always use Marker NAV for conversions.


3. Test Approach and Methodology

Halborn performed a combination of manual code review and automated security testing to balance efficiency, timeliness, practicality, and accuracy in regard to the scope of this assessment. While manual testing is essential to uncover flaws in logic, process, and implementation, automated testing techniques enhance coverage of smart contracts and can quickly identify issues that do not follow security best practices.


The following phases and associated tools were used throughout the assessment:

    • Research into the architecture, purpose, and use of the platform.

    • Manual code review and walkthrough of the smart contracts to identify potential logic issues.

    • Manual testing of all core functions, including deposit, withdraw, vault creation, etc., to validate expected behavior and identify edge-case vulnerabilities.

    • Local testing to simulate contract interactions and validate functional and security assumptions.

    • Fuzz testing with the golang's integrated Fuzzer.


4. RISK METHODOLOGY

Every vulnerability and issue observed by Halborn is ranked based on two sets of Metrics and a Severity Coefficient. This system is inspired by the industry standard Common Vulnerability Scoring System.
The two Metric sets are: Exploitability and Impact. Exploitability captures the ease and technical means by which vulnerabilities can be exploited and Impact describes the consequences of a successful exploit.
The Severity Coefficients is designed to further refine the accuracy of the ranking with two factors: Reversibility and Scope. These capture the impact of the vulnerability on the environment as well as the number of users and smart contracts affected.
The final score is a value between 0-10 rounded up to 1 decimal place and 10 corresponding to the highest security risk. This provides an objective and accurate rating of the severity of security vulnerabilities in smart contracts.
The system is designed to assist in identifying and prioritizing vulnerabilities based on their level of risk to address the most critical issues in a timely manner.

4.1 EXPLOITABILITY

Attack Origin (AO):
Captures whether the attack requires compromising a specific account.
Attack Cost (AC):
Captures the cost of exploiting the vulnerability incurred by the attacker relative to sending a single transaction on the relevant blockchain. Includes but is not limited to financial and computational cost.
Attack Complexity (AX):
Describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability. Includes but is not limited to macro situation, available third-party liquidity and regulatory challenges.
Metrics:
EXPLOITABILITY METRIC (mem_e)METRIC VALUENUMERICAL 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
Exploitability EE is calculated using the following formula:

E=∏meE = \prod m_e

4.2 IMPACT

Confidentiality (C):
Measures the impact to the confidentiality of the information resources managed by the contract due to a successfully exploited vulnerability. Confidentiality refers to limiting access to authorized users only.
Integrity (I):
Measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of data stored and/or processed on-chain. Integrity impact directly affecting Deposit or Yield records is excluded.
Availability (A):
Measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. This metric refers to smart contract features and functionality, not state. Availability impact directly affecting Deposit or Yield is excluded.
Deposit (D):
Measures the impact to the deposits made to the contract by either users or owners.
Yield (Y):
Measures the impact to the yield generated by the contract for either users or owners.
Metrics:
IMPACT METRIC (mIm_I)METRIC VALUENUMERICAL 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
Impact II is calculated using the following formula:

I=max(mI)+∑mI−max(mI)4I = max(m_I) + \frac{\sum{m_I} - max(m_I)}{4}

4.3 SEVERITY COEFFICIENT

Reversibility (R):
Describes the share of the exploited vulnerability effects that can be reversed. For upgradeable contracts, assume the contract private key is available.
Scope (S):
Captures whether a vulnerability in one vulnerable contract impacts resources in other contracts.
Metrics:
SEVERITY COEFFICIENT (CC)COEFFICIENT VALUENUMERICAL VALUE
Reversibility (rr)None (R:N)
Partial (R:P)
Full (R:F)		1
0.5
0.25
Scope (ss)Changed (S:C)
Unchanged (S:U)		1.25
1
Severity Coefficient CC is obtained by the following product:

C=rsC = rs

The Vulnerability Severity Score SS is obtained by:

S=min(10,EIC∗10)S = min(10, EIC * 10)

The score is rounded up to 1 decimal places.
SeverityScore Value Range
Critical9 - 10
High7 - 8.9
Medium4.5 - 6.9
Low2 - 4.4
Informational0 - 1.9

5. SCOPE

REPOSITORIES
(a) Repository: nuva-cosmos-contracts
(b) Assessed Commit ID: e999bef
(c) Items in scope:
  • src/lib.rs
  • src/contract.rs
  • src/error.rs
↓ Expand ↓
Out-of-Scope: Third party dependencies and economic attacks.
(a) Repository: vault
(b) Assessed Commit ID: a7d0f0e
(c) Items in scope:
  • vault-main/keeper/msg_server.go
  • vault-main/module.go
  • vault-main/types/msgs.go
↓ Expand ↓
Out-of-Scope: Third party dependencies and economic attacks.
(a) Repository: nuva-evm-contracts
(b) Assessed Commit ID: 6f48f08
(c) Items in scope:
  • contracts/CustomToken.sol
  • contracts/Depositor.sol
  • contracts/DepositorFactory.sol
↓ Expand ↓
Out-of-Scope: Third party dependencies and economic attacks.
Remediation Commit ID:
Out-of-Scope: New features/implementations after the remediation commit IDs.

6. Assessment Summary & Findings Overview

Critical

0

High

0

Medium

0

Low

9

Informational

5

Security analysisRisk levelRemediation Date
Dust SwapOut Can Burn Shares While Paying Out Zero Assets Due to Floor RoundingLowRisk Accepted - 01/15/2026
Paused Vault Withdrawal Backlog Causes Repeated EndBlocker O(N) ScansLowRisk Accepted - 01/15/2026
ReceiptId Validation Uses Untrimmed Value in StorageLowFuture Release - 01/20/2026
Hardcoded 1:1 Pricing for uylds.fcc Bypasses NAV and Can Cause User Arbitrage if the Peg DeviatesLowSolved - 01/07/2026
NAV Publish Can Panic When TotalShares Exceeds uint64LowSolved - 01/15/2026
Migration Does Not Transfer Accumulated TokensLowFuture Release - 01/20/2026
Unbounded Loop in Destination Address ManagementLowFuture Release - 01/20/2026
Migration Does Not Preserve Destination AddressesLowFuture Release - 01/20/2026
BurnSwapOutReceipt Amount Parameter Not Validated Against ReceiptLowRisk Accepted - 01/20/2026
No Validation of to_address ParameterInformationalFuture Release - 01/20/2026
AML Signer Address Cannot Be RotatedInformationalFuture Release - 01/20/2026
Empty Migration Handler Without Version CheckingInformationalSolved - 01/20/2026
Missing Input Validation in Token CreationInformationalFuture Release - 01/20/2026
Missing Zero-Amount Check in BurnSwapInReceiptInformationalFuture Release - 01/20/2026

7. Findings & Tech Details

7.1 Dust SwapOut Can Burn Shares While Paying Out Zero Assets Due to Floor Rounding

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.2 Paused Vault Withdrawal Backlog Causes Repeated EndBlocker O(N) Scans

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.3 ReceiptId Validation Uses Untrimmed Value in Storage

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.4 Hardcoded 1:1 Pricing for uylds.fcc Bypasses NAV and Can Cause User Arbitrage if the Peg Deviates

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.5 NAV Publish Can Panic When TotalShares Exceeds uint64

//

Low

Description
BVSS
Recommendation
Remediation Comment
Remediation Hash
https://github.com/ProvLabs/vault/commit/11ab317849a69ffbc66e228e742babd133c97593

7.6 Migration Does Not Transfer Accumulated Tokens

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.7 Unbounded Loop in Destination Address Management

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.8 Migration Does Not Preserve Destination Addresses

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.9 BurnSwapOutReceipt Amount Parameter Not Validated Against Receipt

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.10 No Validation of to_address Parameter

//

Informational

Description
BVSS
Recommendation
Remediation Comment

7.11 AML Signer Address Cannot Be Rotated

//

Informational

Description
BVSS
Recommendation
Remediation Comment

7.12 Empty Migration Handler Without Version Checking

//

Informational

Description
BVSS
Recommendation
Remediation Comment
Remediation Hash
https://github.com/ProvLabs/vault/commit/e0c0165b0bd25b270ed434e613d538e22d3c72a1

7.13 Missing Input Validation in Token Creation

//

Informational

Description
BVSS
Recommendation
Remediation Comment

7.14 Missing Zero-Amount Check in BurnSwapInReceipt

//

Informational

Description
BVSS
Recommendation
Remediation Comment

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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Vault, Cosmos & EVM Contracts

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