CVE-2025-6507
📋 TL;DR
This vulnerability in h2o-3 allows attackers to bypass regex filters in JDBC connections by manipulating spaces between parameters, enabling deserialization of untrusted data. Successful exploitation could lead to arbitrary code execution and unauthorized file system access. This affects users running h2o-3 versions before 3.46.0.8.
💻 Affected Systems
- h2oai/h2o-3
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with remote code execution, data exfiltration, and complete control over affected systems
Likely Case
Unauthorized file access and potential code execution leading to data theft or system manipulation
If Mitigated
Limited impact if proper network segmentation and input validation are implemented
🎯 Exploit Status
Exploit details available in public bounty reports; space manipulation bypass makes exploitation straightforward
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.46.0.8
Vendor Advisory: https://github.com/h2oai/h2o-3/commit/f714edd6b8429c7a7211b779b6ec108a95b7382d
Restart Required: Yes
Instructions:
1. Stop h2o-3 service. 2. Update to version 3.46.0.8 or later. 3. Restart the service. 4. Verify the fix is applied.
🔧 Temporary Workarounds
Disable vulnerable JDBC features
allTemporarily disable or restrict JDBC connection functionality until patching
Configure h2o-3 to disable external JDBC connections if not required
Network segmentation
allRestrict network access to h2o-3 services
Implement firewall rules to limit access to trusted IPs only
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure
- Monitor for suspicious JDBC connection attempts and parameter manipulation
🔍 How to Verify
Check if Vulnerable:
Check h2o-3 version; if version is earlier than 3.46.0.8, system is vulnerableCheck Version:
java -jar h2o.jar --versionVerify Fix Applied:
Confirm version is 3.46.0.8 or later and test JDBC parameter filtering📡 Detection & Monitoring
Log Indicators:
- Unusual JDBC connection patterns
- Parameter manipulation attempts with extra spaces
- Deserialization errors
Network Indicators:
- Suspicious JDBC traffic to h2o-3 services
- Unexpected file access patterns
SIEM Query:
source="h2o-3" AND (JDBC OR deserialization OR "parameter injection")