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Vulnerabilities

Vulnerability · CVE-2025-6544

A deserialization vulnerability exists in h2oai/h2o-3 versions <= 3.46.0.8, allowing attackers to read arbitrary system files and execute arbitrary code.

Published Sep 21, 2025 · catalog updated Sep 22, 2025 · A deserialization vulnerability exists

Last checked Oct 26, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-6544. EPSS is 0.92%. Act only if a listed version of A deserialization vulnerability exists is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A deserialization vulnerability exists).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Critical9.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.92%
Remediation
Version ranges on file
Affected products
vendor h2oai h2oai/h2o-3 unspecified <3.46.8

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor h2oai h2oai/h2o-3 unspecified <3.46.8unspecified <3.46.8

How to fix CVE-2025-6544

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-6544. EPSS is 0.92%. Act only if a listed version of A deserialization vulnerability exists is installed.

Which versions are affected?

Compare what you have installed with h2oai h2oai/h2o-3 unspecified <3.46.8 unspecified <3.46.8. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.92%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 21, 2025 · EUVD

    Detected

    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.

  2. Sep 22, 2025 · EUVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2025-6544

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-6544

    30-day exploitation probability 0.92%

    first.org
  • EUVDVulnerability recordEUVD-2025-30380

    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 exp

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 26, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 26, 2026
  • CVE.orgOct 23, 2026
  • EUVDOct 23, 2026