CVE-2025-6544

CRITICAL

h2o-3 <= 3.46.0.8 - Open Redirect

Title source: llm
STIX 2.1

Description

A deserialization vulnerability exists in h2oai/h2o-3 versions <= 3.46.0.8, 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.

Scores

CVSS v3 9.8
EPSS 0.0057
EPSS Percentile 68.8%
Attack Vector NETWORK
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact total

Details

CWE
CWE-502
Status published
Products (3)
ai.h2o/h2o-core 0Maven
h2o/h2o 3.0.0.2 - 3.46.0.8
pypi/h2o 0PyPI
Published Sep 21, 2025
Tracked Since Feb 18, 2026