CVE-2026-3960

A critical remote code execution vulnerability exists in the unauthenticated REST API endpoint /99/ImportSQLTable in H2O-3 version 3.46.0.9 and prior. The vulnerability arises due to insufficient security controls in the parameter blacklist mechanism, which only targets MySQL JDBC driver-specific dangerous parameters. An attacker can bypass these controls by switching the JDBC URL protocol to jdbc:postgresql: and exploiting PostgreSQL JDBC driver-specific parameters such as socketFactory and socketFactoryArg. This allows unauthenticated attackers to execute arbitrary code on the H2O-3 server with the privileges of the H2O-3 process. The issue is resolved in version 3.46.0.10.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/h2oai/h2o-3/commit/b9ae2d3c5220db2dc53753357a783e590364d044	Patch
https://huntr.com/bounties/6954fe04-b905-453f-8c53-205ac8377e0d	Exploit Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:h2o:h2o:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-04-23 10:16

Updated : 2026-06-17 10:44

NVD link : CVE-2026-3960

Mitre link : CVE-2026-3960

CVE.ORG link : CVE-2026-3960

JSON object : View

Products Affected

h2o

h2o

CWE

CWE-94

Improper Control of Generation of Code ('Code Injection')

{"id": "CVE-2026-3960", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-3960", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-04-23T12:25:29.022861Z"}}], "cvssMetricV30": [{"type": "Secondary", "source": "security@huntr.dev", "cvssData": {"scope": "UNCHANGED", "version": "3.0", "baseScore": 5.9, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 2.2}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security@huntr.dev", "affectedData": [{"vendor": "h2oai", "product": "h2oai/h2o-3", "versions": [{"status": "affected", "version": "unspecified", "lessThan": "3.46.0.10", "versionType": "custom"}]}]}], "published": "2026-04-23T10:16:17.813", "references": [{"url": "https://github.com/h2oai/h2o-3/commit/b9ae2d3c5220db2dc53753357a783e590364d044", "tags": ["Patch"], "source": "security@huntr.dev"}, {"url": "https://huntr.com/bounties/6954fe04-b905-453f-8c53-205ac8377e0d", "tags": ["Exploit", "Third Party Advisory"], "source": "security@huntr.dev"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security@huntr.dev", "description": [{"lang": "en", "value": "CWE-94"}]}], "descriptions": [{"lang": "en", "value": "A critical remote code execution vulnerability exists in the unauthenticated REST API endpoint /99/ImportSQLTable in H2O-3 version 3.46.0.9 and prior. The vulnerability arises due to insufficient security controls in the parameter blacklist mechanism, which only targets MySQL JDBC driver-specific dangerous parameters. An attacker can bypass these controls by switching the JDBC URL protocol to jdbc:postgresql: and exploiting PostgreSQL JDBC driver-specific parameters such as socketFactory and socketFactoryArg. This allows unauthenticated attackers to execute arbitrary code on the H2O-3 server with the privileges of the H2O-3 process. The issue is resolved in version 3.46.0.10."}], "lastModified": "2026-06-17T10:44:31.060", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:h2o:h2o:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "53A9A943-C0AC-4312-BF4D-033D14678ED4", "versionEndExcluding": "3.46.0.10"}], "operator": "OR"}]}], "sourceIdentifier": "security@huntr.dev"}