CVE-2025-6544NVD

Vulnerability Summary

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.

Severity Level

CRITICAL(9.8)

Published Date

Sep 21, 2025

Last Modified

Oct 5, 2026

Exploitation Status

No confirmed exploitation yet

EPSS Score (30-Day)

0.92%Probability

Root Weakness (CWE)

CWE-502: Unknown/Unlisted Weakness ↗

Refer to the official MITRE database for detailed architectural specifications regarding this weakness.

CVSS v3.0 Base Metrics — Score 9.8 (CRITICAL)

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

Affected & Patched Versions

Affected Versions

H2o H2o >= 3.0.0.2 and <= 3.46.0.8

Patched Versions

Not provided by NVD for this CVE.

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