What’s Vulnerable › Vulnerabilities

CVE-2026-3960: Remote Code Execution in h2oai/h2o-3

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-04-23 · updated 2026-10-26
• Weakness: CWE-94

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.

Affected products

• h2oai/h2o-3: before 3.46.0.10 — fixed in 3.46.0.10

How to fix

Upgrade to a fixed version: h2oai/h2o-3 3.46.0.10. Check the vendor advisory for mitigations.

References

• https://github.com/h2oai/h2o-3/commit/b9ae2d3c5220db2dc53753357a783e590364d044
• https://huntr.com/bounties/6954fe04-b905-453f-8c53-205ac8377e0d

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