Vulnerability report

Exploited in the wild High confidence Not in CISA KEV

CVE-2023-6038

h2oai/h2o-3

h2oai/h2o-3 · unspecified to <= latest

Watch CVE-2023-6038 Browse KEV feed
Severity
CVSS 9.3 · Critical
Confidence
High
Exploit status
Exploited in the wild
EPSS
4.3%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2023-6038 is an unauthenticated vulnerability affecting h2oai/h2o-3. A Local File Inclusion (LFI) vulnerability exists in the h2o-3 REST API, allowing unauthenticated remote attackers to read arbitrary files on...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is high. Also confirmed by third-party sources.

Who is affected?

h2oai/h2o-3 unspecified to <= latest.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

h2oai/h2o-3

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.

h2oai Affected
h2oai/h2o-3
Through latest
Published
16 Nov 2023
Exploitation Reported
16 Nov 2023
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

nuclei_scanner

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

The Shadowserver

Recorded 16 Nov 2023

A trusted third party reported exploitation.

Proof of concept available

Nuclei Templates

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

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Source Added
The Shadowserver First 2023-11-16 16:06 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2023/CVE-2023-6038.yaml 25 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.0

9.3 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

EPSS

4.3%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Missing Authorization CWE-862

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

H2O ImportFiles - Local File Inclusion

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. 14:20 UTC

    Public PoC available

    Public proof-of-concept code published

  2. 00:00 UTC

    Nuclei template available

    Scanner coverage available

  3. 16:06 UTC

    CVE published

    Vulnerability disclosed publicly

  4. 16:06 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  5. 18:15 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2023-6038

Sample API response 
{
  "cve_id": "CVE-2023-6038",
  "confidence": "High",
  "cvss_score": 9.3,
  "cvss_estimated": false,
  "epss_score": 0.0434,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}