RHSA-2021:5206MediumCVSS 7.5

Red Hat Security Advisory: log4j security update

Published
December 20, 2021
Last Modified
September 22, 2026

🔗 CVE IDs covered (1)

CVE-2021-4104 →

📋 Description

CVE-2021-4104 — log4j: Remote code execution in Log4j 1.x when application is configured to use JMSAppender

🎯 Affected products87

  • Red Hat Enterprise Linux Client (v. 7)
  • Red Hat Enterprise Linux Client Optional (v. 7)
  • Red Hat Enterprise Linux ComputeNode Optional (v. 7)
  • Red Hat Enterprise Linux Server (v. 6 ELS)
  • Red Hat Enterprise Linux Server (v. 7)
  • Red Hat Enterprise Linux Server AUS (v. 7.3)
  • Red Hat Enterprise Linux Server AUS (v. 7.4)
  • Red Hat Enterprise Linux Server AUS (v. 7.6)
  • Red Hat Enterprise Linux Server AUS (v. 7.7)
  • Red Hat Enterprise Linux Server E4S (v. 7.6)
  • Red Hat Enterprise Linux Server E4S (v. 7.7)
  • Red Hat Enterprise Linux Server Optional (v. 6 ELS)
  • Red Hat Enterprise Linux Server Optional (v. 7)
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.3)
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.4)
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.6)
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.7)
  • Red Hat Enterprise Linux Server Optional E4S (v. 7.6)
  • Red Hat Enterprise Linux Server Optional E4S (v. 7.7)
  • Red Hat Enterprise Linux Server Optional TUS (v. 7.6)
  • Red Hat Enterprise Linux Server Optional TUS (v. 7.7)
  • Red Hat Enterprise Linux Server TUS (v. 7.6)
  • Red Hat Enterprise Linux Server TUS (v. 7.7)
  • Red Hat Enterprise Linux Workstation (v. 7)
  • Red Hat Enterprise Linux Workstation Optional (v. 7)
  • log4j-0:1.2.14-6.5.el6_10.i686 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • log4j-0:1.2.14-6.5.el6_10.s390x as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • log4j-0:1.2.14-6.5.el6_10.src as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • log4j-0:1.2.14-6.5.el6_10.x86_64 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • log4j-0:1.2.17-16.el7_3.noarch as a component of Red Hat Enterprise Linux Server AUS (v. 7.3)
  • +57 more not shown

✅ Remediation

For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Workaround: These are the possible mitigations for this flaw for releases version 1.x: - Comment out or remove JMSAppender in the Log4j configuration if it is used - Remove the JMSAppender class from the classpath. For example: ``` zip -q -d log4j-*.jar org/apache/log4j/net/JMSAppender.class ``` - Restrict access for the OS user on the platform running the application to prevent modifying the Log4j configuration by the attacker.

🔗 References (5)