What is CVE-2021-4104?

CVE-2021-4104 is a high-severity vulnerability in Apache Log4j, classified under Deserialization of Untrusted Data. CVSS score: 7.5/10. Published 2021-12-14.

How severe is CVE-2021-4104?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2021-4104 known to be exploited?

78 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Deserialization in Apache Log4j

CVE-2021-4104

JMSAppender in Log4j 1.2 is vulnerable to deserialization of untrusted data when the attacker has write access to the Log4j configuration. The attacker can provide TopicBindingName and TopicConnectionFactoryBindingName configurations causing JMSAppender to perform JNDI requests that result in remote code execution in a similar fashion to CVE-2021-44228. Note this issue only affects Log4j 1.2 when specifically configured to use JMSAppender, which is not the default. Apache Log4j 1.2 reached end of life in August 2015. Users should upgrade to Log4j 2 as it addresses numerous other issues from the previous versions.

Vulnerability class: Insecure Deserialization

EPSS: 0.811 (99.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Apache Log4j — versions 1.2
Apache Software Foundation Log4j 1.x — versions Apache Log4j 1.2 1.2.x
Oracle Advanced_supply_chain_planning — versions 12.1, 12.2
Oracle Business_intelligence — versions 5.9.0.0.0, 12.2.1.3.0, 12.2.1.4.0
Oracle Business_process_management_suite — versions 12.2.1.3.0, 12.2.1.4.0
Oracle Communications_eagle_ftp_table_base_retrieval — versions 4.5
Oracle Communications_messaging_server — versions 8.1
Oracle Communications_network_integrity — versions 7.3.6
Oracle Communications_offline_mediation_controller — versions 12.0.0.5.0
Oracle Communications_unified_inventory_management — versions 7.3.4, 7.3.5, 7.4.1

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

Public proof-of-concept exploits

References

security@apache.org
security@apache.org
security@apache.org
security@apache.org (third-party-advisory)
security@apache.org (mailing-list)
security@apache.org
security@apache.org
security@apache.org
security@apache.org
security@apache.org

Frequently asked questions

What is CVE-2021-4104?: CVE-2021-4104 is a high-severity vulnerability in Apache Log4j, classified under Deserialization of Untrusted Data. CVSS score: 7.5/10. Published 2021-12-14.
How severe is CVE-2021-4104?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2021-4104 known to be exploited?: 78 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.