Overview

Recently, NSFOCUS CERT detected that H2O-3 released a security update to fix the H2O-3 JDBC deserialization vulnerability (CVE-2025-6507); This vulnerability is a bypass of CVE-2024-45758 and CVE-2024-10553. Due to the deserialization flaw in the system’s JDBC connection processing logic, an unauthenticated attacker can bypass existing regular expression filtering by manipulating spaces between parameters, thereby achieving arbitrary file reading and remote code execution. The CVSS score is 9.8. At present, the vulnerability details and PoC have been made public. Relevant users are requested to take measures to protect themselves as soon as possible.

H2O-3 is an open source, distributed, scalable machine learning platform for quickly building and deploying machine learning models on big data.

Reference link: https://nvd.nist.gov/vuln/detail/CVE-2025-6507

Scope of Impact

Affected versions

• H2O-3 <= 3.46.0.7
• H2O-3 <= 3.47.0.99999

Unaffected version

• H2O-3 >= 3.46.0.8

Mitigation

Official upgrade

At present, the official has released a new version to fix this vulnerability. Affected users are requested to upgrade their protection as soon as possible. Download link:

https://github.com/h2oai/h2o-3/commit/f714edd6b8429c7a7211b779b6ec108a95b7382d

Temporary protective measures

If the relevant users are temporarily unable to perform upgrade operations, access restrictions can be imposed on the H2O-3 port (default 54321) without affecting business.

Statement

This advisory is only used to describe a potential risk. NSFOCUS does not provide any commitment or promise on this advisory. NSFOCUS and the author will not bear any liability for any direct and/or indirect consequences and losses caused by transmitting and/or using this advisory. NSFOCUS reserves all the rights to modify and interpret this advisory. Please include this statement paragraph when reproducing or transferring this advisory. Do not modify this advisory, add/delete any information to/from it, or use this advisory for commercial purposes without permission from NSFOCUS.

About NSFOCUS

NSFOCUS, a pioneering leader in cybersecurity, is dedicated to safeguarding telecommunications, Internet service providers, hosting providers, and enterprises from sophisticated cyberattacks.

Founded in 2000, NSFOCUS operates globally with over 4000 employees at two headquarters in Beijing, China, and Santa Clara, CA, USA, and over 50 offices worldwide. It has a proven track record of protecting over 25% of the Fortune Global 500 companies, including four of the five largest banks and six of the world’s top ten telecommunications companies.

Leveraging technical prowess and innovation, NSFOCUS delivers a comprehensive suite of security solutions, including the Intelligent Security Operations Platform (ISOP) for modern SOC, DDoS Protection, Continuous Threat Exposure Management (CTEM) Service and Web Application and API Protection (WAAP). All the solutions and services are augmented by the Security Large Language Model (SecLLM), ML, patented algorithms and other cutting-edge research achievements developed by NSFOCUS.

The post H2O-3 JDBC Deserialization Vulnerability (CVE-2025-6507) appeared first on NSFOCUS, Inc., a global network and cyber security leader, protects enterprises and carriers from advanced cyber attacks..

*** This is a Security Bloggers Network syndicated blog from NSFOCUS, Inc., a global network and cyber security leader, protects enterprises and carriers from advanced cyber attacks. authored by NSFOCUS. Read the original post at: https://nsfocusglobal.com/h2o-3-jdbc-deserialization-vulnerability-cve-2025-6507/