CVE-2023-6038 — h2o-core
CRITICALCVE-2023-6038 is a critical-severity (CVSS 9.3) CWE-862 vulnerability in ai.h2o:h2o-core. 1 public exploit reference exists, so weaponization risk is real. No vendor fix is recorded yet; mitigation options are listed below.
H2O local file inclusion vulnerability
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-2023-6038.
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-2023-6038 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 377,166 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
ai.h2o:h2o-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
A Local File Inclusion (LFI) vulnerability exists in the h2o-3 REST API, allowing unauthenticated remote attackers to read arbitrary files on the server with the permissions of the user running the h2o-3 instance. This issue affects the default installation and does not require user interaction. The vulnerability can be exploited by making specific GET or POST requests to the ImportFiles and ParseSetup endpoints, respectively. This issue was identified in version 3.40.0.4 of h2o-3.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | ai.h2o:h2o-core | all versions | No fix |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ai.h2o:h2o-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of ai.h2o:h2o-core has shipped for CVE-2023-6038 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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-2023-6038 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-6038. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
How to detect CVE-2023-6038
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2023-6038 -u https://target- Template
- H2O ImportFiles - Local File Inclusion
- Severity
- high
- Impact
- Unauthenticated attackers can read any file on the server via the ImportFiles endpoint, potentially exposing sensitive data including database contents and application code.
- Remediation
- Update H2O to a version that implements proper authentication and authorization controls for the ImportFiles endpoint.
Template by ProjectDiscovery nuclei-templates (danmcinerney, byt3bl33d3r), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2023-6038 in your dependencies?
O3 Security finds CVE-2023-6038 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.