CVE-2025-6544

⛔ critical

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.

CVSS Score

9.8

Critical

EPSS Score

0.3

Exploit Probability

Published Date

2025-09-21

First Seen: 2026-01-05

📊 Relative Risk Intelligence

This CVE is Very High Risk - more severe than 90.4% of all 321,566 vulnerabilities in our database.

#30,777

Top 10% most severe

Severity Percentile

🎯 CISA SSVC Assessment Updated: Sep 22, 2025

🔍 Exploitation Status

Poc

Proof-of-concept available

⚙️ Automatable

YES

Can be exploited automatically

💥 Technical Impact

Total

Complete system compromise possible

SSVC data provided by CISA

Last Modified 2025-10-08

Source NVD 🔗

CVSS Vector 3.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE IDs (Weakness Types)

CWE-502

📦 Affected Products 1

Vendor	Product	Status	Affected Versions
h2o	h2o	Affected	≥ 3.0.0.2 ≤ 3.46.0.8

🔗 References 2

https://github.com/h2oai/h2o-3/commit/0298ee348f5c73...

Patch

https://huntr.com/bounties/53f35a0f-d644-4f82-93aa-8...

Exploit Third Party Advisory

🔗 Related CVEs 6

CVE ID	Severity	CVSS	EPSS	Summary	Published
CVE-2026-8750	🔶 medium	5.3	0.0	A vulnerability was identified in h2oai h2o-3 up to 7402. Affected by this issue is the function importFiles of the file...	2026-05-17
CVE-2026-8751	⚠️ high	7.3	0.0	A security flaw has been discovered in h2oai h2o-3 up to 7402. This affects the function importBinaryModel of the file h...	2026-05-17
CVE-2026-8752	🔶 medium	5.3	0.0	A weakness has been identified in h2oai h2o-3 up to 7402. This vulnerability affects the function exec of the file h2o-c...	2026-05-17
CVE-2026-3960	⛔ critical	9.8	0.3	A critical remote code execution vulnerability exists in the unauthenticated REST API endpoint /99/ImportSQLTable in H2O...	2026-04-23
CVE-2025-10768	🔶 medium	6.3	0.1	A flaw has been found in h2oai h2o-3 up to 3.46.08. The impacted element is an unknown function of the file /99/ImportSQ...	2025-09-21
CVE-2025-10769	🔶 medium	6.3	0.1	A vulnerability has been found in h2oai h2o-3 up to 3.46.08. This affects an unknown function of the file /99/ImportSQLT...	2025-09-21

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