CVE-2025-6544

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2025-09-22. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Elevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
9.8
EG Score
9.8(medium)
EG Risk
75(Attend)
EG Risk 75/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
59%
KEV
Not listed

Published

September 21, 2025

Last Modified

June 17, 2026

Advisory Details (2)

Auto-updated Sep 13, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
generic

huntr - The world's first bug bounty platform for AI/ML

https://huntr.com/bounties/53f35a0f-d644-4f82-93aa-89fe7e0aed40
github_commit

commit 0298ee348f5c (h2oai/h2o-3)

Fix landed in h2oai/h2o-3 commit 0298ee348f5c — awaiting tagged release

https://github.com/h2oai/h2o-3/commit/0298ee348f5c73673b7b542158081e79605f5f25

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
mavenai.h2o:h2o-core—ghsa
piph2o—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(2 across 2 ecosystems)
Maven(1)
PackageVulnerable rangeFixed inDependents
ai.h2o:h2o-core0.1.10 ... 3.8.3.4 (253 versions)——
PyPI(1)
PackageVulnerable rangeFixed inDependents
h2o3.10.0.10 ... 3.46.0.7 (118 versions)——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 27× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 147 total refreshes for this CVE.

  1. 2026-09-18 19:27 UTCEPSS rescore
  2. 2026-09-17 19:30 UTCEPSS rescore
  3. 2026-09-16 14:07 UTCEPSS rescore
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  6. 2026-09-13 16:46 UTCEPSS rescore
  7. 2026-09-12 23:06 UTCOSV refresh
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  23. 2026-08-25 03:26 UTCOSV refresh
  24. 2026-08-24 14:16 UTCEPSS rescore
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  1. 2026-08-21 23:48 UTCEPSS rescore
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  14. 2026-08-08 20:25 UTCOSV refresh
  15. 2026-08-08 16:36 UTCEPSS rescore
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  23. 2026-07-30 16:27 UTCEPSS rescore
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  25. 2026-07-27 14:13 UTCEPSS rescore
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  28. 2026-07-25 14:17 UTCEPSS rescore
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  30. 2026-07-24 14:17 UTCEPSS rescore
  31. 2026-07-23 19:11 UTCOSV refresh
  32. 2026-07-23 14:18 UTCEPSS rescore
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  34. 2026-07-23 03:01 UTCEG score recompute
  35. 2026-07-22 14:08 UTCEPSS rescore
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  50. 2026-07-13 06:12 UTCEPSS rescore
  51. 2026-07-12 05:46 UTCEPSS rescore
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  53. 2026-07-11 08:27 UTCEPSS rescore
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  55. 2026-07-09 19:10 UTCEPSS rescore
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  57. 2026-07-07 13:46 UTCEPSS rescore
  58. 2026-07-06 16:27 UTCEPSS rescore
  59. 2026-07-06 13:41 UTCOSV refresh
  60. 2026-07-06 02:23 UTCEPSS rescore
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  65. 2026-07-01 15:06 UTCEPSS rescore
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  68. 2026-06-28 14:07 UTCEPSS rescore
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  70. 2026-06-28 04:56 UTCEPSS rescore
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  72. 2026-06-27 03:08 UTCEPSS rescore
  73. 2026-06-25 13:49 UTCEPSS rescore
  74. 2026-06-25 13:49 UTCEPSS rescore
  75. 2026-06-24 14:05 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2025-6544?
CVE-2025-6544 is a critical vulnerability published on September 21, 2025. 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…
When was CVE-2025-6544 disclosed?
CVE-2025-6544 was first published in the National Vulnerability Database on September 21, 2025, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-6544 actively exploited?
CVE-2025-6544 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 41.3% of all scored CVEs.
What is the CVSS score of CVE-2025-6544?
CVE-2025-6544 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2025-6544?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-6544, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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