CVE intelligenceCISA KEVRansomware use

CVE-2021-44228

Apache Log4j2 Remote Code Execution Vulnerability

Published Dec 10, 2021Sources checked Sep 12, 2026

10.0CRITICALCVSS out of 10

What this means

Actively exploited

CISA lists CVE-2021-44228 in its Known Exploited Vulnerabilities catalog, which means exploitation has been observed. The entry applies to Apache Log4j2.

For all affected software assets for which updates exist, the only acceptable remediation actions are: 1) Apply updates; OR 2) remove affected assets from agency networks. Temporary mitigations using one of the measures provided at https://www.cisa.gov/uscert/ed-22-02-apache-log4j-recommended-mitigation-measures are only acceptable until updates are available.

CISA KEVListedObserved exploitation

EPSS100.0%Estimated 30-day exploitation probability

Ransomware useReported by CISACISA KEV ransomware field

Threat actors3Source-linked actor relationships

Overview

What is CVE-2021-44228?

Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.