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CVE-2026-3960

H2o remote code execution

9.8 CRITICALPublic exploitEPSS 1.03%
  1. Published23 Apr 2026

Description

A critical remote code execution vulnerability exists in the unauthenticated REST API endpoint /99/ImportSQLTable in H2O-3 version 3.46.0.9 and prior. The vulnerability arises due to insufficient security controls in the parameter blacklist mechanism, which only targets MySQL JDBC driver-specific dangerous parameters. An attacker can bypass these controls by switching the JDBC URL protocol to jdbc:postgresql: and exploiting PostgreSQL JDBC driver-specific parameters such as socketFactory and socketFactoryArg. This allows unauthenticated attackers to execute arbitrary code on the H2O-3 server with the privileges of the H2O-3 process. The issue is resolved in version 3.46.0.10.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

H2o< 3.46.0.10

Remediation

Fixed in
H2o≥ 3.46.0.10

References

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Frequently asked

Is CVE-2026-3960 being actively exploited?

CVE-2026-3960 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 1.03%.

How severe is CVE-2026-3960?

CVE-2026-3960 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 1.03% probability of exploitation.

Which products are affected by CVE-2026-3960?

Affected products include H2o.

How do I fix CVE-2026-3960?

Upgrade affected software to a fixed version, for example H2o 3.46.0.10 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-3960 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.