CVE-2025-6544

9.8 CRITICAL
Published: September 21, 2025 Modified: October 08, 2025

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://huntr.com/bounties/53f35a0f-d644-4f82-93aa-89fe7e0aed40
Source: security@huntr.dev
Exploit Third Party Advisory
https://huntr.com/bounties/53f35a0f-d644-4f82-93aa-89fe7e0aed40
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Third Party Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.8 / 10.0
EPSS (Exploit Probability)
0.2%
43th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

h2o