How severe is CVE-2021-42392?

CVE-2021-42392 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-42392?

CVE-2021-42392 affects the following packages: com.h2database:h2 (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-42392?

Update com.h2database:h2 to 2.0.206 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-42392 is resolved across your whole dependency graph.

How do I detect CVE-2021-42392 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.h2database:h2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-42392 if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Is CVE-2021-42392 actively exploited in the wild?

Yes. There are 3 known exploit references for CVE-2021-42392, including 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-42392?

CVE-2021-42392 has an EPSS (Exploit Prediction Scoring System) score of 83.2%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2021-42392?

CVE-2021-42392 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Is there exploit tooling available for CVE-2021-42392?

A Nuclei detection template exists for CVE-2021-42392, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-42392 published, and has it been updated?

CVE-2021-42392 was published on January 10, 2022 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

CRITICAL severity

CVE-2021-42392 — h2

CRITICAL

CVE-2021-42392 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in com.h2database:h2. 3 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for com.h2database:h2 — see the affected versions and patch details below.

RCE in H2 Console

Also known asGHSA-h376-j262-vhq6

Published

Jan 10, 2022

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

3 known

Exploitation data as of Nov 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

83.2%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

☕com.h2database:h2

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Impact

H2 Console in versions since 1.1.100 (2008-10-14) to 2.0.204 (2021-12-21) inclusive allows loading of custom classes from remote servers through JNDI.

H2 Console doesn't accept remote connections by default. If remote access was enabled explicitly and some protection method (such as security constraint) wasn't set, an intruder can load own custom class and execute its code in a process with H2 Console (H2 Server process or a web server with H2 Console servlet).

It is also possible to load them by creation a linked table in these versions, but it requires ADMIN privileges and user with ADMIN privileges has full access to the Java process by design. These privileges should never be granted to untrusted users.

Patches

Since version 2.0.206 H2 Console and linked tables explicitly forbid attempts to specify LDAP URLs for JNDI. Only local data sources can be used.

Workarounds

H2 Console should never be available to untrusted users.

-webAllowOthers is a dangerous setting that should be avoided.

H2 Console Servlet deployed on a web server can be protected with a security constraint: https://h2database.com/html/tutorial.html#usingH2ConsoleServlet If webAllowOthers is specified, you need to uncomment and edit <security-role> and <security-constraint> as necessary. See documentation of your web server for more details.

References

This issue was found and privately reported to H2 team by JFrog Security's vulnerability research team with detailed information.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`com.h2database:h2`	≥ 1.1.100&&< 2.0.206	2.0.206`com.h2database:h2:2.0.206`

Affected Products

3 products · 5 configurations

debian linuxdebian

3 versions

9.010.011.0

Application

h2h2database

≥ 1.1.000 && ≤ 2.0.204

range

Application

communications cloud native core policyoracle

1 version

1.15.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

The org.h2.util.JdbcUtils.getConnection method of the H2 database takes …

github.comGithubJan 2022

Report on jfrog.com

jfrog.comNVDJan 2022

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.h2database:h2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update com.h2database:h2 to 2.0.206 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-42392 is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

How to detect CVE-2021-42392

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2021-42392 -u https://target

Template: H2 Database Console - JNDI Injection RCE
Severity: critical
Impact: An unauthenticated attacker can trigger an outbound JNDI lookup to a server they control, leading to remote code execution on the host running the H2 web console.
Remediation: Upgrade H2 database to version 2.0.206 or later, and disable the web console (spring.h2.console.enabled=false) or restrict access to it.

Template by ProjectDiscovery nuclei-templates (i-am-paradox), MIT licensed. View the full template. Scan only systems you are authorised to test.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

In OpenShift Container Platform (OCP) the openshift4/ose-metering-presto container image ships the vulnerable version of h2, but as it uses default configuration the impact by this vulnerability is LOW. Additionally, the Presto component is part of the OCP Metering stack and since the release of OCP 4.6, the Metering…

Product	Fixed in	Advisory
Red Hat JBoss Enterprise Application Platform	`com.h2database/h2:1.4.197.redhat-00004`	RHSA-2022:4922
Red Hat JBoss Enterprise Application Platform 7.3 EUS for RHEL 7	`eap7-hal-console-0:3.2.17-1.Final_redhat_00001.1.el7eap`	RHSA-2025:1747
Red Hat JBoss Enterprise Application Platform 7.4 for RHEL 8	`eap7-h2database-0:1.4.197-2.redhat_00004.1.el8eap`	RHSA-2022:4919
Red Hat JBoss Enterprise Application Platform 7.4 on RHEL 7	`eap7-h2database-0:1.4.197-2.redhat_00004.1.el7eap`	RHSA-2022:4918
Red Hat Single Sign-On 7	`h2`	RHSA-2022:6787
Red Hat Single Sign-On 7.5 for RHEL 7	`rh-sso7-keycloak-0:15.0.8-1.redhat_00001.1.el7sso`	RHSA-2022:6782
Red Hat Single Sign-On 7.5 for RHEL 8	`rh-sso7-keycloak-0:15.0.8-1.redhat_00001.1.el8sso`	RHSA-2022:6783
Red Hat Single Sign-On 7.6.1	`h2`	RHSA-2022:7417

UbuntuCRITICAL

USN-5365-1Ubuntu USN-6834-1Ubuntu

Frequently Asked Questions

### Impact H2 Console in versions since 1.1.100 (2008-10-14) to 2.0.204 (2021-12-21) inclusive allows loading of custom classes from remote servers through JNDI. H2 Console doesn't accept remote connections by default. If remote access was enabled explicitly and some protection method (such as security constraint) wasn't set, an intruder can load own custom class and execute its code in a process with H2 Console (H2 Server process or a web server with H2 Console servlet). It is also possible to load them by creation a linked table in these versions, but it requires `ADMIN` privileges and use

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