Is CVE-2026-8751 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-8751 being exploited in the wild.

How severe is CVE-2026-8751?

High severity, with a CVSS score of 7.3, published 17 May 2026.

Is there a fix for CVE-2026-8751?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-8751 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-8751?

Check whether you run H2O.ai H2O-3 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-8751: h2oai h2o-3 insecure deserialization in importBinaryModel

CVE-2026-8751 · Severity: high · CVSS 7.3 · Published 2026-05-17

H2O-3 is an open-source machine learning platform used for building and deploying predictive models. A security vulnerability in its model import feature allows an attacker to upload and execute malicious code on the server. This could lead to a complete takeover of the server, theft of sensitive data, or disruption of business operations.

Technologies: H2O.ai H2O-3. Vendors: H2O.ai.

Quick answers

Is CVE-2026-8751 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-8751 being exploited in the wild.
How severe is CVE-2026-8751?: High severity, with a CVSS score of 7.3, published 17 May 2026.
Which products and versions are affected?: H2O.ai H2O-3 up to 7402.
Is there a fix for CVE-2026-8751?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-8751 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-8751?: Check whether you run H2O.ai H2O-3 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A pre-authentication insecure deserialization vulnerability exists in H2O-3's 'importBinaryModel' function within 'h2o-core/src/main/java/hex/Model.java'. The vulnerability stems from the use of 'Keyed.readAll()' on untrusted model bytes, which allows an attacker to restore a serialized 'custom_metric_func' reference. By first uploading a malicious JAR to the Distributed Key-Value (DKV) store via '/3/PutKey.bin', an attacker can craft a binary model that, when imported and subsequently used for scoring, triggers the 'DkvClassLoader' to load and execute the attacker-controlled JAR. This results in arbitrary code execution within the server JVM. The vendor has reportedly not responded to the disclosure, and public exploits are available.

Affected products

h2oai h2o-3 up to 7402

Timeline

2026-05-17: advisory: Initial disclosure via VulDB and NVD

References

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