Date of engagement: 10th December 2025 - 29th December 2025
-
Michal BajorPrincipal advisor
Engagement Dashboard
Audit results
Guvenkaya conducted a comprehensive security assessment of the Sailor Lend web application. During this engagement, 2 findings were reported: 1 Critical and 1 High severity issue. The critical finding includes a remote code execution vulnerability through React2Shell (CVE-2025-55182) affecting React Server Components. All findings have been addressed by the Sailor Lend team.
Engagement record
- Client
- Sailor Lend
- System
- Sailor Lend web application
- Review period
- 10th December 2025 - 29th December 2025
- Reviewed baseline
93fbf4f33c97999cb74ff109f355b6c73bc722f8- Paths in scope
- 1
- Principal advisor
- Michal Bajor
Timeline
- Review start10th December 2025
- Draft report29th December 2025
- Final report17th March 2026
Findings by severity
Finding status at final report
Remediation complexity
Impact
Likelihood
Advisory and Client
The advisory
Guvenkaya specializes in security for digital assets and financial infrastructure, from smart contracts and protocols to applications, infrastructure, custody and cryptography.
Our team, including the sitting Heads of Security at Gauntlet and Agora, brings experience from Kraken, OpenZeppelin, Binance, ZKsync, Nillion, Invicti and EY. Across the team: 200+ security reviews, $30B+ in volume secured, 13 published cryptography research papers, and credentials including OSCP, OSWE and CISM.
- Every reviewer has a public bio and is named before you sign. We match expertise to your system, with a principal leading scoping and checking findings.
The client
Sailor Lend is a trustless, self-custodial DeFi lending protocol built on the NEAR blockchain. The platform enables users to obtain instant loans using BTC, ZEC, or SOL as collateral without requiring KYC verification. Users can deposit stablecoins for lending to earn interest, while borrowers can leverage their crypto assets to access liquidity. The protocol implements liquidation mechanisms, interest rate calculations, and Pyth price oracle integrations.
Scope and Review Boundaries
Review depths
- Deep
- Line-by-line review with explicit attack hypotheses, adversarial reasoning about state transitions, and reproduction attempts for each hypothesis that survived reading.
- Supporting
- The code was read for its effect on a reviewed flow. Behaviour outside that effect was not assessed.
- Targeted
- Entry points were exercised or triaged against the flow's security properties rather than read in full.
This is the code we read, and how closely. 1 paths are in scope. Each path links to the file at the reviewed commit.
| Path | Review depth | Scope note |
|---|---|---|
src | Deep | Sailor Lend Web Application |
Out of scope
The audit included reviewing the code for security vulnerabilities, coding practices, and architecture. The audit does not include a review of the dependencies or external contracts such as Pyth Oracle and FT contracts.
Assessment Framework
Guvenkaya rates findings by likelihood and impact so remediation can be prioritized by technical risk, business context, and the decision the engagement is meant to support.
Rating chain applied to every finding
- 01 Likelihood Likely, possible or rare
- 02 Impact Severe, moderate or negligible
- 03 Severity Derived from the matrix below
- 04 Remediation complexity Simple, moderate or difficult
- 05 Status Not fixed, fixed, acknowledged or scheduled
Impact
| Impact | What it means here |
|---|---|
| Severe | Exploitation could result in critical loss or compromise, such as full system control, substantial financial loss, or severe reputational damage. |
| Moderate | Exploitation may lead to limited data loss, partial compromise, moderate financial impact, or noticeable degradation of services. |
| Negligible | Exploitation has minimal impact, such as minor data exposure without significant consequences or slight inconvenience without substantial disruption. |
Likelihood
| Likelihood | What it means here |
|---|---|
| Likely | The vulnerability is easily discoverable and not overly complex to exploit. |
| Possible | The vulnerability presents some challenges either in discovery or in the complexity of the attack. |
| Rare | The vulnerability is either very difficult to discover or complex to exploit, or both. |
This matrix provides a nuanced view, taking into account both the ease of discovering a vulnerability and the complexity involved in exploiting it.
| Attack Complexity \ Discovery Ease | Obvious | Concealed | Hidden |
|---|---|---|---|
| Complex | Possible | Rare | Rare |
| Moderate | Likely | Possible | Rare |
| Straightforward | Likely | Possible | Possible |
Severity
| Severity | What it means here |
|---|---|
| Critical | Assigned to vulnerabilities with severe impact and a likely likelihood of exploitation. |
| High | For vulnerabilities with either severe impact but only a possible likelihood, or moderate impact with a likely likelihood. |
| Medium | Used for vulnerabilities with severe impact but a rare likelihood, moderate impact with a possible likelihood, or negligible impact with a likely likelihood. |
| Low | For vulnerabilities with moderate impact and rare likelihood, or negligible impact with a possible likelihood. |
| Informational | The lowest severity rating, typically for vulnerabilities with negligible impact and a rare likelihood of exploitation. |
| Likelihood \ Impact | Severe | Moderate | Negligible |
|---|---|---|---|
| Likely | Critical | High | Medium |
| Possible | High | Medium | Low |
| Rare | Medium | Low | Informational |
Remediation complexity
This measures how difficult it is to remediate a finding once it has been identified.
| Remediation complexity | What it means here |
|---|---|
| Simple | Patches or fixes are readily available and easily implemented. |
| Moderate | Requires some time and resources to remediate, but well within the capabilities of most organizations. |
| Difficult | Remediation requires significant resources, specialized skills, or substantial changes to systems or architecture. |
Finding status
This tracks the client's response to each finding and whether remediation has been completed, accepted, or scheduled.
| Status | What it means here |
|---|---|
| Not Fixed | Indicates that the vulnerability has been identified but no remedial action has been taken yet. This status is crucial for newly discovered vulnerabilities or those awaiting prioritization. |
| Fixed | This status is applied when the vulnerability has been successfully remediated. It implies that appropriate measures, such as patching, configuration changes, or architectural modifications, have been implemented to resolve the issue. |
| Acknowledged | This status is used for vulnerabilities that have been recognized, but for various reasons (such as risk acceptance, cost, or other business decisions), have not been fixed. It indicates that the risk posed by the vulnerability is known and has been consciously accepted. |
| Scheduled | This status indicates that the vulnerability has been acknowledged and a plan is in place to fix it in the future. It signifies that while remediation hasn't yet occurred, the issue has been prioritized and is part of the planned development roadmap. |
Findings Summary
Findings register
| Finding | Impact | Likelihood | Severity | Remediation complexity | Status |
|---|---|---|---|---|---|
| GUV-1: Vulnerable to React2Shell | Severe | Likely | Critical | Simple | Fixed |
| GUV-2: Hardcoded Password in Source Code | Moderate | Likely | High | Simple | Fixed |
Detailed Findings
GUV-1: Vulnerable to React2Shell
Description
The application is vulnerable to React2Shell (CVE-2025-55182), a critical remote code execution (RCE) vulnerability affecting React Server Components. The project currently uses React 19.0.0, which falls within the vulnerable version range (19.0.0 through 19.2.0).
This vulnerability stems from unsafe deserialization within React's "Flight" protocol, allowing unauthenticated attackers to execute arbitrary code on the server by sending specially crafted HTTP requests. The application uses Next.js 15.1.4 with the App Router, which relies on React Server Components and is therefore affected.
The vulnerability was confirmed using https://github.com/assetnote/react2shell-scanner tool.
Recommendation
We recommend updating the react version to a non-vulnerable version.
Remediation
Sailor Lend team has fixed this issue in commit 3446235a0abc82377a266bc8c8a056c3523130fc
GUV-2: Hardcoded Password in Source Code
Description
The source code contains a hardcoded password that is checked before accessing the web application.
const passwordIsCorrect = (value: string) => { return value === "satoshi";};Recommendation
We recommend avoiding hard-coding sensitive values in the code. The best approach would be to send the password to the backend and do the hash-based comparison there.
Remediation
Sailor Lend team has fixed this issue in commit 3446235a0abc82377a266bc8c8a056c3523130fc
The web version and the PDF (13 pages) are generated from the same source. The report as first delivered is kept in the public reports archive.