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
8 foundWeaponization
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.
- fullhunt/log4j-scan★ 3423
A fully automated, accurate, and extensive scanner for finding log4j RCE CVE-2021-44228
updated Oct 29, 2026
- kozmer/log4j-shell-poc★ 1844
A Proof-Of-Concept for the CVE-2021-44228 vulnerability.
updated Oct 29, 2026
- christophetd/log4shell-vulnerable-app★ 1144
Spring Boot web application vulnerable to Log4Shell (CVE-2021-44228).
updated Oct 19, 2026
- Puliczek/CVE-2021-44228-PoC-log4j-bypass-words★ 952
🐱💻 ✂️ 🤬 CVE-2021-44228 - LOG4J Java exploit - WAF bypass tricks
updated Oct 17, 2026
- logpresso/CVE-2021-44228-Scanner★ 864
Vulnerability scanner and mitigation patch for Log4j2 CVE-2021-44228
updated Oct 24, 2026
- f0ng/log4j2burpscanner★ 839
CVE-2021-44228 Log4j2 BurpSuite Scanner,Customize ceye.io api or other apis,including internal networks
updated Oct 29, 2026
- mergebase/log4j-detector★ 641
A public open sourced tool. Log4J scanner that detects vulnerable Log4J versions (CVE-2021-44228, CVE-2021-45046, etc) on your file-system within any application. It is able to even find Log4J instances that are hidden several layers deep. Works on Linux, Windows, and Mac, and everywhere else Java runs, too! TAG_OS_TOOL, OWNER_KELLY, DC_PUBLIC
updated Oct 13, 2026
- corretto/hotpatch-for-apache-log4j2★ 497
An agent to hotpatch the log4j RCE from CVE-2021-44228.
updated Oct 24, 2026
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. We also found 8 public GitHub repositories referencing this CVE.
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
Impactr finds and proves whether CVE-2021-44228 — or flaws like it — are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.