High

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

  • Disclosed: 17.12.2021
  • Updated: 11.10.2026 12:21

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:
bash
# install zip command if you don't have
apt-get update && apt-get install -y zip
# remove the class
zip -d clickhouse-jdbc-bridge*.jar ru/yandex/clickhouse/jdbcbridge/internal/log4j/net/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.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) ru.yandex.clickhouse:clickhouse-jdbc-bridge < 2.0.7 2.0.7

References

CVSS score 8.1/10
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-502
Platform
Java / Kotlin (Maven)
Package
ru.yandex.clickhouse:clickhouse-jdbc-bridge
Disclosed
17.12.2021
Updated
11.10.2026 12:21

Sources and licenses

OSV / GitHub Advisory Database - GHSA-3w6p-8f82-gw8r - CC BY 4.0

Vulnerability history: ru.yandex.clickhouse:clickhouse-jdbc-bridge

All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.

This is the only known vulnerability of this package.

Know which vulnerabilities affect your application

With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.

Connect your application
DockRay newsletter

Application security in your inbox

Important vulnerabilities, actionable guidance and practical advice for your applications. Choose your technologies and follow what matters to your project.

  • A daily digest of new vulnerabilities, critical ones included.
  • Notifications about important updates.
  • Practical advice on application security and monitoring.

Leave empty to receive updates for every technology.

Free to subscribe. Unsubscribe with one click in any email.