Smart Contract Assessment Audit | Oro

Summary

100% of all REPORTED Findings have been addressed

About this report

Assessment Type

Assurance Assessment

Date of Engagement

May 22nd, 2026 - May 29th, 2026

Source Code

oroswap-core

Assessed Commit ID

8737739

Severity Breakdown

0Risk Accepted
3Acknowledged
13Solved
16All Findings

Critical0
High1
- 1Solved
Medium2
- 2Solved
Low4
- 4Solved
Informational9
- 6Solved
- 3Ack.

INTRODUCTION#

Oro engaged Halborn to conduct a security assessment on their CosmWasm contracts beginning on May 22nd, 2026 and ending on May 29th, 2026. The security assessment was scoped to the repository listed with commit hash, and further details in the Scope section of this report.

ORO is a multi-chain protocol, and the audited scope is the set of CosmWasm contracts implementing the on-chain portion of its token lifecycle — handling distribution, staking, and wrapped-asset issuance. It includes an airdrop module for allocating and vesting tokens to eligible users, a staking module where users deposit the staking token into a per-address stake registry and earn reward-stream payouts pro-rata against their stake balance, and a wrapper module that locks a source token and mints a corresponding wrapped denomination through the chain's tokenfactory. Together, these contracts support the core token lifecycle around distribution, staking incentives, unbonding, and wrapped-token issuance.

ASSESSMENT SUMMARY#

The team at Halborn assigned a full-time security engineer to verify the security of the smart contracts. The security engineer is a blockchain and smart-contract security expert with advanced penetration testing, smart-contract hacking, and deep knowledge of multiple blockchain protocols.

The purpose of this assessment is to:

Ensure that smart contract functions operate as intended
Identify potential security issues with the smart contracts

In summary, Halborn identified some improvements to reduce the likelihood and impact of risks, which were mostly addressed by the Oro team. The main recommendations included:

Make reward accounting transfer aware, or use non-transferable staking positions while side rewards are active.
Reject zero-value claims before marking user eligibility as claimed.
Reject claim transactions that include unexpected attached native funds.
Define lifetime reward token limits clearly, or safely retire expired reward programs after all outstanding obligations are settled.
Align user-facing claim status with the actual conditions required for a successful claim.
Calculate bonus funding requirements from remaining unpaid obligations instead of total historical allocations.

TEST APPROACH AND METHODOLOGY#

Halborn performed a combination of manual and automated security testing to balance efficiency, timeliness, practicality, and accuracy in regard to the scope of this assessment. While manual testing is recommended to uncover flaws in logic, process, and implementation; automated testing techniques help enhance coverage of the code and can quickly identify items that do not follow the security best practices. The following phases and associated tools were used during the assessment:

Research into architecture, purpose, and use of the platform.
Manual code read and walk through.
Manual Assessment of use and safety for the critical Rust variables and functions in scope to identify any arithmetic related vulnerability classes.
Architecture related logical controls.
Cross contract call controls.
Scanning of Rust files for vulnerabilities (cargo audit)
Review and improvement of integration tests.
Verification of integration tests and implementation of new ones.

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 ( $m_e$ )	METRIC VALUE	NUMERICAL VALUE
Attack Origin (AO)	Arbitrary (AO:A)	1
Attack Origin (AO)	Specific (AO:S)	0.2
Attack Cost (AC)	Low (AC:L)	1
	Medium (AC:M)	0.67
	High (AC:H)	0.33
Attack Complexity (AX)	Low (AX:L)	1
	Medium (AX:M)	0.67
	High (AX:H)	0.33

Exploitability

E

is calculated using the following formula:

$E = \prod m_e$

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 ( $m_I$ )	METRIC VALUE	NUMERICAL VALUE
Confidentiality (C)	None (C:N)	0
	Low (C:L)	0.25
	Medium (C:M)	0.5
	High (C:H)	0.75
	Critical (C:C)	1
Integrity (I)	None (I:N)	0
	Low (I:L)	0.25
	Medium (I:M)	0.5
	High (I:H)	0.75
	Critical (I:C)	1
Availability (A)	None (A:N)	0
	Low (A:L)	0.25
	Medium (A:M)	0.5
	High (A:H)	0.75
	Critical (A:C)	1
Deposit (D)	None (D:N)	0
	Low (D:L)	0.25
	Medium (D:M)	0.5
	High (D:H)	0.75
	Critical (D:C)	1
Yield (Y)	None (Y:N)	0
	Low (Y:L)	0.25
	Medium (Y:M)	0.5
	High (Y:H)	0.75
	Critical (Y:C)	1

Impact

I

is calculated using the following formula:

$I = max(m_I) + \frac{\sum{m_I} - max(m_I)}{4}$

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 ( $C$ )	COEFFICIENT VALUE	NUMERICAL VALUE
Reversibility ( $r$ )	None (R:N)	1
	Partial (R:P)	0.5
	Full (R:F)	0.25
Scope ( $s$ )	Changed (S:C)	1.25
Scope ( $s$ )	Unchanged (S:U)	1

Severity Coefficient

C

is obtained by the following product:

$C = rs$

The Vulnerability Severity Score

S

is obtained by:

$S = min(10, EIC * 10)$

The score is rounded up to 1 decimal places.

Critical	High	Medium	Low	Informational
9 - 10	7 - 8.9	4.5 - 6.9	2 - 4.4	0 - 1.9

Scope#

(a) Repository:oroswap-core

(b) Assessed Commit ID:8737739bd8f1c6b75257f98e801c8ad84b4dabcf

3 files

contracts / tokenomics

3 files

airdrop

staking

wrapper

Out-of-Scope:Third party dependencies and economic attacks.

f5df9fda7f38301c554fb76cf4361b84bd896562 ae63a56158052016f2002661a3492c47b5be470c b04e0d41bc8c42c77582f07566575316012c5e87 df4d1e66cc9c3809cb68991b1a7b28fd2157dda2 b82085d13e150c503fabc6f8f5ad6a701e7d12dd 088b33d2b8fa5830307280dda9bba9742839f8db cf21e9892faae69f72cca52326dddc48d3be9621 97dd4ee3b45fa4362718f4967eee3d912d56bdc0 a277ee73126daf575e3a6a4ad9caeff894abb8d7

Out-of-Scope: New features/implementations after the remediation commit IDs.

Assessment Summary & Findings Overview#

#	Title	Severity	Score	Status
HAL-01	Transferable shares allow duplicated side reward accrual	High	7.5	Solved06/04/2026
HAL-02	Zero payout claims permanently consume user eligibility	Medium	5.0	Solved06/01/2026
HAL-03	Cumulative burn accounting can permanently exhaust wrapper minting capacity	Medium	5.0	Solved06/05/2026
HAL-04	Claims can silently retain attached native funds	Low	3.4	Solved06/01/2026
HAL-05	Expired reward denoms permanently consume reward slots	Low	3.4	Solved06/03/2026
HAL-06	Inactive airdrops can appear as claimable	Low	2.5	Solved06/01/2026
HAL-07	APY bonus solvency checks overstate remaining obligations	Low	2.5	Solved06/01/2026
HAL-08	Unbounded airdrop scans can make fund recovery increasingly expensive	Informational	1.7	Solved06/02/2026
HAL-09	Denom admin handoff can leave the wrapper in exit only mode	Informational	1.7	Acknowledged06/10/2026
HAL-10	Tokenfactory reply parsing does not validate the returned denom	Informational	1.7	Solved06/03/2026
HAL-11	Migration handlers do not enforce forward only versioning	Informational	1.6	Solved06/02/2026
HAL-12	Withdrawal guard relies on caller supplied token type	Informational	1.6	Solved06/02/2026
HAL-13	Pause authority queries are not paginated	Informational	0.8	Acknowledged06/10/2026
HAL-14	Release build configuration disables declared overflow checks	Informational	0.8	Solved06/02/2026
HAL-15	Unbonding period increases take effect immediately	Informational	0.8	Acknowledged06/10/2026
HAL-16	Hook destination is not validated before dispatch	Informational	0.0	Solved06/03/2026

Tokenfactory reply parsing does not validate the returned denom

Informational

1.7AO:A/AC:L/AX:M/R:N/S:U/C:N/A:N/I:L/D:N/Y:NAO:A/AC:L/AX:M/R:N/S:U/C:N/A:N/I:L/D:N/Y:N

Description

Recommendation

Remediation Comment

Addressed in:

088b33d2b8fa5830307280dda9bba9742839f8db

HAL-11Solved

Migration handlers do not enforce forward only versioning

Informational

1.6AO:A/AC:L/AX:H/R:N/S:U/C:N/A:N/I:M/D:N/Y:NAO:A/AC:L/AX:H/R:N/S:U/C:N/A:N/I:M/D:N/Y:N

Description

Recommendation

Remediation Comment

Addressed in:

Addressed in:

088b33d2b8fa5830307280dda9bba9742839f8db

Disclaimer#

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.