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 causi…

Vulnerability class: Insecure Deserialization

EPSS: 0.722 (98.8th 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

Weakness classification (CWE)

Public proof-of-concept exploits

References

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.