CVE-2026-8751
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 · uneditedA security flaw has been discovered in h2oai h2o-3 up to 7402. This affects the function importBinaryModel of the file h2o-core/src/main/java/hex/Model.java of the component JAR Handler. Performing a manipulation results in deserialization. The attack is possible to be carried out remotely. The exploit has been released to the public and may be used for attacks. 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 confidenceA deserialization vulnerability exists in H2O-3's JAR Handler component, specifically in the importBinaryModel function within hex/Model.java. Attackers can exploit this by providing malicious serialized Java objects through the model import functionality, potentially achieving remote code execution. The public exploit and critical CVSS score indicate straightforward exploitation.
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<= 7402CVSS 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
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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 checksWork through these to decide whether this CVE applies to you.
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Identify H2O versionRun 'h2o --version' or check the H2O JAR file name/version metadata. H2O versions are typically displayed in the web UI footer or in startup logs.Affected if The installed version is H2O version 7402 or any earlier version (versions are represented numerically, lower numbers indicate earlier releases).
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Confirm H2O service is runningCheck if the H2O process is active and the web UI (Flow) or REST API is accessible on the configured port (typically 54321).Affected if H2O is running and network-accessible, as the vulnerability is exploitable through the model import functionality.
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Verify model import capability is accessibleCheck if the importBinaryModel function is exposed via the H2O REST API endpoint or web interface. Look for model import options in the Flow UI or API paths related to model/import.Affected if The model import functionality is available and accessible to users or unauthenticated attackers.
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Check network exposureReview firewall rules, binding address configuration, and authentication settings for the H2O service. Determine if the H2O interface is bound to non-localhost addresses.Affected if H2O is bound to a publicly reachable network interface or trusted network without proper access controls.
A user is affected if their H2O installation is version 7402 or earlier and the model import functionality is accessible over the network.
Generated from the published advisory. Verify against your own configuration.
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 dataRestrict or disable the importBinaryModel functionality until a patched version is available; if required, implement strict allowlist-based deserialization controls and validate all JAR inputs before processing. Network segmentation provides additional defense-in-depth.
- Consultation8.0 h
- Implementation24.0 h
- Testing16.0 h
- Review / QA12.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-8751 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-8751 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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