Using JMSAppender in log4j configuration may lead to deserialization of untrusted data

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.1 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact ClickHouse JDBC Bridge uses slf4j-log4j12 1.7.32, which depends on log4j 1.2.17. It allows a remote attacker to execute code on the server, if you changed default log4j configuration by adding JMSAppender and an insecure JMS broker. Patches The patch version 2.0.7 removed log4j dependency by replacing slf4j-log4j12 to slf4j-jdk14. Logging configuration is also changed from log4j.properties to logging.properties. Workarounds 1. Do NOT change log4j configuration to use JMSAppender along with insecure JMS broker 2. Alternatively, you can issue below command to remove JMSAppender.class: References Please refer to CVE-2021-4104 to read more. For more information If you have any questions or comments about this advisory, please feel free to open an issue in the repository.

Published by the source

17 Dec 2021, 20:42 UTC

Last modified by the source

9 Jan 2023, 05:06 UTC

Source last checked

26 Oct 2026, 15:53 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3w6p-8f82-gw8r

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# Patch Next advisory brief: GHSA-3w6p-8f82-gw8r

Advisory: Using JMSAppender in log4j configuration may lead to deserialization of untrusted data
IDs: GHSA-3w6p-8f82-gw8r
Record: https://patchnext.com/advisories/ghsa-3w6p-8f82-gw8r (revision 1, source checked 26 Oct 2026, 15:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: ru.yandex.clickhouse:clickhouse-jdbc-bridge 2.0.7. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven ru.yandex.clickhouse:clickhouse-jdbc-bridge: affected < 2.0.7; fixed in 2.0.7

## Suggested inspection (read-only)
- Maven ru.yandex.clickhouse:clickhouse-jdbc-bridge: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on ru.yandex.clickhouse:clickhouse-jdbc-bridge.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-3w6p-8f82-gw8r (GitHub-reviewed advisory GHSA-3w6p-8f82-gw8r lists affected ranges: Maven ru.yandex.clickhouse:clickhouse-jdbc-bridge >=0 <2.0.7)

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