H2O affected by a deserialization vulnerability
A deserialization vulnerability exists in h2oai/h2o-3 versions <= 3.46.0.7, allowing attackers to read arbitrary system files and execute arbitrary code. The vulnerability arises from improper handling of JDBC connection parameters, which can be exploited by bypassing regular expression checks and using double URL encoding. This issue impacts all users of the affected versions.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | ai.h2o:h2o-core | <= 3.46.0.7 | no fix |
| Python (PyPI) | h2o | <= 3.46.0.7 | no fix |
References
- CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-502- Platform
- Java / Kotlin (Maven), Python (PyPI)
- Package
ai.h2o:h2o-core, h2o- Disclosed
- 22.09.2025
- Updated
- 11.10.2026 12:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-5w3j-gwgh-4rfv - CC BY 4.0
OSV / GitHub Advisory Database - PYSEC-2026-349 - PyPA Advisory Database; CC BY 4.0
Vulnerability history: h2o
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 17
- First → latest
- 12.2023 04.2026
- Without a fix
- 14
- Exploited in attacks
- 0
Severity breakdown
- Critical 6
- High 9
- Medium 2
Disclosures per year
- 2023: 1
- 2024: 3
- 2025: 11
- 2026: 2
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H2O affected by a deserialization vulnerability this entry
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