Apache Log4j2 Remote Code Execution Vulnerability
Apache Software Foundation — Apache Log4j2
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.
10.0
100.0%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Published
- Dec 10, 2021
- Modified
- Aug 11, 2026
- Added to KEV
- Dec 10, 2021
- Federal patch due
- Dec 24, 2021
CISA 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.
Weakness classification
Affected packages
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2021-44228, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2021-44228 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.
References
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- packetstormsecurity.com
- seclists.org
- seclists.org
- seclists.org
- openwall.com
How this class of flaw gets exploited
Frequently asked questions
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.
How severe is CVE-2021-44228?
CVE-2021-44228 has a CVSS base score of 10.0 out of 10 (CVSS 3.1).
Is CVE-2021-44228 actively exploited in the wild?
Yes. CVE-2021-44228 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Dec 10, 2021, meaning CISA has confirmed evidence of active exploitation. It is also flagged as used in ransomware campaigns.
What is the EPSS score for CVE-2021-44228?
100.0% - meaning FIRST.org's EPSS model estimates a 100.0% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).
Is there exploit tooling available for CVE-2021-44228?
Yes - a public Nuclei template referencing CVE-2021-44228 exist in public repositories we checked.
What type of vulnerability is CVE-2021-44228?
CVE-2021-44228 is classified under CWE-20, CWE-917, CWE-502, CWE-400 (CWE-20 Improper Input Validation).
Cross-checked against
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