CVE-2025-6544

H2O affected by a deserialization vulnerability

Published 21 Sep 2025Modified 5 Oct 2026CWE 502

In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

GHSA9.8CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Trivy's own label is CRITICAL. Rated critical by GHSA.

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.

Affected packages and fixed versions

Source	Package	Fixed in
maven::GitHub Security Advisory Maven	ai.h2o:h2o-core	no fix listed
pip::GitHub Security Advisory pip	h2o	no fix listed

References

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KnowsThe scanner refreshes its vulnerability database every six hours.
FindsEvery admitted image is rescanned every 24 hours by default (scan.rescanInterval). When Trivy rates this vulnerability critical for the image's package source, it appears in the image's findings by name. Findings without a fix are left out unless includeUnfixed is on.
Tells youA critical_finding event goes to the channels subscribed to it: e-mail, Slack, Teams, a webhook, Jira, GitLab or GitHub.
RefusesWith a policy that blocks critical findings, a pod with this image is refused at admission, a rollback to it included. Pods already running are not evicted.
RecordsEach decision is recorded with the policy that ran and its hash, then sealed under a signed checkpoint.

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Vulnerability data compiled from the Trivy vulnerability database (trivy-db, Aqua Security, Apache License 2.0), which aggregates third-party advisories. CVE records are published by The MITRE Corporation under the CVE Terms of Use; CVE is a trademark of MITRE. This product uses data from the NVD API but is not endorsed or certified by the NVD. Severity, titles and advisory data from the GitHub Advisory Database (CC BY 4.0), Red Hat security data (CC BY 4.0) and the other sources linked on each entry. Entries may be summarised or re-formatted; the linked original is the authoritative record.