---
id: "CVE-2021-44228"
kind: "vulnerability"
aliases: ["CVE-2021-44228"]
title: "Apache Log4j2: Apache Log4j2 Remote Code Execution Vulnerability"
severity: "critical"
cvss: 10.0
epss: 0.99999
exploited: true
status: "open"
category: "package"
products: [{"name": "Apache Log4j2", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["enterprise", "exploited", "java", "log4j", "package", "ransomware", "self-hosted"]
not_affected_if: ["no-log4j2-present", "non-java-stack"]
published_at: "2021-12-10T00:00:00+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-44228", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-44228", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-44228", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Apache Log4j2: Apache Log4j2 Remote Code Execution Vulnerability

Apache Log4j2 logging library evaluates JNDI lookups in logged messages, so attacker-controlled input can make the server load and run remote code. An attacker gets code execution on any server that logs their input.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Apache Log4j2 affected ? fixed ?

## How to check

Search for log4j-core jars in application directories and fat jars (for example: find / -name 'log4j-core*.jar' 2>/dev/null) and check their version.

## Fix

Upgrade log4j-core to a fixed release per the Apache Log4j2 security page; CISA requires applying updates or removing the affected asset.
Until patched, the CISA interim mitigations apply (see the CISA ED 22-02 mitigation page cited in the sources).

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-44228
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-44228
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-44228

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_