H2oApplication

CVE-2026-8750

HIGH · 7.5 CVSS v3.1 Published 2026-05-17
Fix available
A fix is available. Upgrade to after 7402 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability was identified in h2oai h2o-3 up to 7402. Affected by this issue is the function importFiles of the file h2o-core/src/main/java/water/persist/PersistNFS.java of the component ImportFile API. Such manipulation leads to information disclosure. The attack can be executed remotely. The exploit is publicly available and might be used. The vendor was contacted early about this disclosure but did not respond in any way.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

An information disclosure vulnerability exists in the importFiles function of PersistNFS.java in h2o-3 up to version 7402. The ImportFile API does not properly validate or restrict file paths/inputs during NFS import operations, allowing a remote attacker to potentially access sensitive files or information beyond the intended scope. The exploit is publicly available and requires no authentication.

MitigationImplement strict input validation and path sanitization in the importFiles function to prevent directory traversal; add authentication and authorization checks to the ImportFile API; restrict file access to intended directories only. Consider network segmentation to limit exposure until a patch is available.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
H2oApplication
Affected:<= 7402

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed H2o version
    Locate the H2o installation and check the version number (typically found in version file, about screen, or startup logs). Compare against the affected range: version <= 7402 is vulnerable.
    Affected if Installed H2o version is 7402 or lower
  2. Verify ImportFile API accessibility
    Confirm the H2o REST API is exposed (typically on port 54321 or configured port). The ImportFile endpoint (such as /3/ImportFiles or similar NFS import endpoints) should be accessible over the network.
    Affected if The ImportFile API endpoint is reachable without authentication
  3. Check for NFS import configuration
    Look for PersistNFS.java configuration files or NFS-related settings in the H2o deployment. This may appear as NFS mount configurations or import source settings in H2o's configuration directory.
    Affected if NFS import functionality is configured or enabled in the environment
  4. Assess network exposure
    Determine if the H2o web interface/API port is exposed to untrusted networks. Check firewall rules, network ACLs, and bind addresses to see if the service is accessible from outside trusted networks.
    Affected if The H2o service port is accessible from untrusted or public networks without authentication protection
  5. Review authentication settings
    Examine H2o authentication configuration to confirm whether the ImportFile API requires valid credentials. The CVE states the exploit requires no authentication.
    Affected if The ImportFile API does not require authentication or uses weak/no authorization controls

You are affected if H2o version is 7402 or lower AND the ImportFile API for NFS imports is accessible over the network without proper authentication or path validation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 7402
Interim mitigation

Implement strict input validation and path sanitization in the importFiles function to prevent directory traversal; add authentication and authorization checks to the ImportFile API; restrict file access to intended directories only. Consider network segmentation to limit exposure until a patch is available.

Fix this in H2o Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-8750 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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