CVE-2021-44228

10 Known exploited Used in ransomware

Apache Log4j2 Remote Code Execution Vulnerability

CVSS: 10, critical critical CVSS v3.1
EPSS, next 30 days: 100% higher than 99.9% of scored CVEs
Exploitation: Confirmed in the wild
Published: 10 Dec 20214 years ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 10 Dec 2021 and links it to ransomware activity. US federal agencies had to remediate by 24 Dec 2021, a deadline that has passed.

Required action. 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.

Description

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.

Details

Vendor: Apache
Product: Apache Log4j2
Weakness: CWE-20 (opens in a new tab)
Status: Analyzed
Updated: 11 Aug 2026
Assigner: security@apache.org

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

References 52

Exploit code 22

14 more

Patches and fixes 3

Advisories 24

16 more

Other references 3

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Apache CVEs

Every Apache CVE we hold

Same vendor in what we hold, not a known link between the flaws.

CVE-2026-34486 Apache Tomcat Missing Encryption of Sensitive Data Vulnerability KEV EPSS 7% 7.5, high
CVE-2026-34197 Apache ActiveMQ Improper Input Validation Vulnerability KEV EPSS 15% 8.8, high
CVE-2025-24813 Apache Tomcat Path Equivalence Vulnerability KEV EPSS 100% 9.8, critical
CVE-2024-45195 Apache OFBiz Forced Browsing Vulnerability KEV EPSS 100% 7.5, high
CVE-2024-38856 Apache OFBiz Incorrect Authorization Vulnerability KEV EPSS 99% 9.8, critical
CVE-2024-38475 Apache HTTP Server Improper Escaping of Output Vulnerability KEV EPSS 100% 9.1, critical
CVE-2024-32113 Apache OFBiz Path Traversal Vulnerability KEV EPSS 100% 9.8, critical
CVE-2024-27348 Apache HugeGraph-Server Improper Access Control Vulnerability KEV EPSS 99% 9.8, critical

Beyond this page

Is CVE-2021-44228 in your network?

This page tells you how dangerous CVE-2021-44228 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2021-44228 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

EXYS7600 OCELOT

Find it before attackers do

Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2021-44228 comes with the devices to patch.
Learn more about EXYS7600 OCELOT
EXYS7950 KONDRA

Detect it if it's exploited

Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.
Learn more about EXYS7950 KONDRA

Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.