Unauthenticated code execution via encoded JDBC parameters
Published Sep 21, 2025 · Updated Sep 21, 2025
Deserialization in H2O-3 before 3.46.8 allows remote attackers to read system files and execute code through crafted JDBC URLs. SQLManager.validateJdbcUrl checked disallowed JDBC parameters against the still-encoded URL, so double encoding concealed dangerous MySQL options until downstream decoding. The attack requires network access to an H2O endpoint that accepts JDBC connection data; file reads and code execution occur in the server process context.
Summary
What happened
Deserialization in H2O-3 before 3.46.8 allows remote attackers to read system files and execute code through crafted JDBC URLs. SQLManager.validateJdbcUrl checked disallowed JDBC parameters against the still-encoded URL, so double encoding concealed dangerous MySQL options until downstream decoding. The attack requires network access to an H2O endpoint that accepts JDBC connection data; file reads and code execution occur in the server process context.
The record
- CVE
- CVE-2025-6544
- Published
- Sep 21, 2025
- Updated
- Sep 21, 2025
- Vendor
- H2O.ai
- Product
- H2O-3
- Classifications
- CWE-502, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 21, 2025CVE publishedPublication date reported by the CVE source.
- Sep 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <3.46.8
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- huntr.dev JDBC deserialization proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo