CVE-2025-59049 is a high-severity (CVSS 7.5) Path Traversal vulnerability in @mockoon/commons-server. A fix is available for @mockoon/commons-server — see the affected versions and patch details below.
Mockoon has a Path Traversal and LFI in the static file serving endpoint
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-59049.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-59049 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@mockoon/commons-servernpm@mockoon/clinpmDescription
Summary
A mock API configuration for static file serving following the same approach presented in the documentation page, where the server filename is generated via templating features from user input is vulnerable to Path Traversal and LFI, allowing an attacker to get any file in the mock server filesystem. The issue may be particularly relevant in cloud hosted server instances
Details
In sendFileWithCallback(code) and sendFile(code) the filePath variable is parsed using TemplateParser
let filePath = TemplateParser({
shouldOmitDataHelper: false,
// replace backslashes with forward slashes, but not if followed by a dot (to allow helpers with paths containing properties with dots: e.g. {{queryParam 'path.prop\.with\.dots'}})
content: routeResponse.filePath.replace(/\\(?!\.)/g, '/'),
environment: this.environment,
processedDatabuckets: this.processedDatabuckets,
globalVariables: this.globalVariables,
request: serverRequest,
envVarsPrefix: this.options.envVarsPrefix
});
The path extracted from the request parameters used when composing the final file path is not sanitized and is vulnerable to path traversal exploits (e.g. ../../../../../etc/passwd)
PoC
Test setup
The issue has been tested with mockoon-cli, using the Docker image mockoon/cli:latest
# Folder setup
mkdir mockoon-test
cd mockoon-test
# put config.json in mockooon-test dir
mkdir static
# Run container
docker run -d --mount type=bind,source=./config.json,target=/data,readonly -v ./static:/static -p 3000:3000 mockoon/cli:latest -d data -p 3000
Payload to reproduce
Browsing directly to http://localhost:3000/static/%2F..%2F..%2F..%2F..%2F..%2Fetc%2Fpasswd is going to display the /etc/passwd file in the container filesystem
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @mockoon/commons-server | all versions | 9.2.0npm install @mockoon/commons-server@9.2.0 |
| 📦npm | @mockoon/cli | all versions | 9.2.0npm install @mockoon/cli@9.2.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @mockoon/commons-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @mockoon/commons-server to 9.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-59049 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-59049 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-59049. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
How to detect CVE-2025-59049
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2025-59049 -u https://target- Template
- Mockoon < 9.2.0 - Path Traversal
- Severity
- high
- Impact
- Attackers can read arbitrary files from the mock server filesystem through path traversal in static file serving, potentially exposing sensitive configuration and credential files.
- Remediation
- Upgrade Mockoon to version 9.2.0 or later that properly validates and restricts file paths in template processing.
Template by ProjectDiscovery nuclei-templates (iamnoooob, rootxharsh, pdresearch), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2025-59049 in your dependencies?
O3 Security finds CVE-2025-59049 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.