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CVE-2025-6544

CRITICALCVSS 9.8/10EPSS 0.84%

Last modified

CVE-2025-6544 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 0.84% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.0
9.8/10

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

EPSS Probability
0.84%

53.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
H2oH2o>= 3.0.0.2, <= 3.46.0.8

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is 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. 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.
How severe is CVE-2025-6544?
CVE-2025-6544 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.84% probability of exploitation in the next 30 days.
How do I fix CVE-2025-6544?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST