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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.92%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.0
- 9.8 CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.92% probability · 58th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-502
- Affected
- h2o/h2o
- Source
- security@huntr.dev
References
- https://github.com/h2oai/h2o-3/commit/0298ee348f5c73673b7b542158081e79605f5f25Patch
- https://huntr.com/bounties/53f35a0f-d644-4f82-93aa-89fe7e0aed40Exploit, Third Party Advisory
- https://huntr.com/bounties/53f35a0f-d644-4f82-93aa-89fe7e0aed40Exploit, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.