CVE-2026-3960
H2O-3 is Vulnerable to Code Injection
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.
How to fix CVE-2026-3960
To remediate CVE-2026-3960, upgrade the affected package to a fixed version below.
- —upgrade to 3.46.0.10 or later
Is CVE-2026-3960 being exploited?
Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 3.46.0.10
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.9 | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |