How severe is CVE-2021-44228?

CVE-2021-44228 has a CVSS score of 10/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-44228?

CVE-2021-44228 affects the following packages: org.apache.logging.log4j:log4j-core (Maven), org.apache.logging.log4j:log4j-core (Maven), org.apache.logging.log4j:log4j-core (Maven), com.guicedee.services:log4j-core (Maven), org.xbib.elasticsearch:log4j (Maven), uk.co.nichesolutions.logging.log4j:log4j-core (Maven), org.ops4j.pax.logging:pax-logging-log4j2 (Maven), org.ops4j.pax.logging:pax-logging-log4j2 (Maven), and 2 more. Ecosystems affected: Maven.

How do I fix CVE-2021-44228?

Update org.apache.logging.log4j:log4j-core to 2.15.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-44228 is resolved across your whole dependency graph.

How do I detect CVE-2021-44228 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.logging.log4j:log4j-core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2021-44228 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2021-44228?

O3 pinpoints whether CVE-2021-44228 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2021-44228 actively exploited in the wild?

Yes. There are 377 known exploit references for CVE-2021-44228, including 3 documented proof-of-concept exploits on Exploit-DB and 50 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-44228?

CVE-2021-44228 has an EPSS (Exploit Prediction Scoring System) score of 100.0%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2021-44228 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2021-44228 (Apache Log4j2 Remote Code Execution Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2021-12-10. CISA required all US federal civilian agencies to remediate this vulnerability by 2021-12-24. The required action was: 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. This CVE has been used in known ransomware campaigns. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2021-44228?

CVE-2021-44228 is classified as Improper Input Validation (CWE-20), Uncontrolled Resource Consumption (CWE-400), Deserialization of Untrusted Data (CWE-502), Expression Language Injection (CWE-917). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Is there exploit tooling available for CVE-2021-44228?

A Nuclei detection template exists for CVE-2021-44228, meaning automated scanners can fingerprint it. 8 Metasploit modules reference CVE-2021-44228, which lowers the barrier to weaponization. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-44228 published, and has it been updated?

CVE-2021-44228 was published on December 10, 2021 and was last updated on July 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2021-12-10 — agencies required to remediate by 2021-12-24 · Ransomware

☕ Maven

CVE-2021-44228

CRITICAL

Remote code injection in Log4j

Also known asGHSA-jfh8-c2jp-5v3q

Published

Dec 10, 2021

Updated

Jul 8, 2026

Affected

10 pkgs

Patched

7 / 10

Exploits

377 known

EPSS Exploitation Probability

via FIRST.org ↗

100.0%probability of exploitation in next 30 days

Very High Risk100th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

10 pkgs affected

☕org.apache.logging.log4j:log4j-core☕org.apache.logging.log4j:log4j-core☕org.apache.logging.log4j:log4j-core☕com.guicedee.services:log4j-core☕org.xbib.elasticsearch:log4j☕uk.co.nichesolutions.logging.log4j:log4j-core☕org.ops4j.pax.logging:pax-logging-log4j2☕org.ops4j.pax.logging:pax-logging-log4j2+2 more

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

10 total 7 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.logging.log4j:log4j-core`	≥ 2.13.0&&< 2.15.0	2.15.0
☕Maven	`org.apache.logging.log4j:log4j-core`	≥ 2.0-beta9&&< 2.3.1	2.3.1
☕Maven	`org.apache.logging.log4j:log4j-core`	≥ 2.4&&< 2.12.2	2.12.2
☕Maven	`com.guicedee.services:log4j-core`	all versions	No fix
☕Maven	`org.xbib.elasticsearch:log4j`	all versions	No fix
☕Maven	`uk.co.nichesolutions.logging.log4j:log4j-core`	all versions	No fix

Exploits & PoCs

377

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-50592remotejava

Apache Log4j 2 - Remote Code Execution (RCE)

by kozmer · Dec 14, 2021

Exploit-DB Source

EDB-50590remotejava

Apache Log4j2 2.14.1 - Information Disclosure

by leonjza · Dec 14, 2021

Exploit-DB Source

EDB-51183remotejava

AD Manager Plus 7122 - Remote Code Execution (RCE)

by Chan Nyein Wai · Apr 1, 2023

Exploit-DB Source

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.logging.log4j:log4j-core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.apache.logging.log4j:log4j-core to 2.15.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-44228 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2021-44228 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2021-44228. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-44228 in your dependencies?

O3 detects CVE-2021-44228 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2021-44228

EPSS Exploitation Probability

Blast Radius

Description

Affected Packages

Detection & mitigation playbook

Detect

Fix

Workarounds

How O3 protects you

Frequently Asked Questions

Is CVE-2021-44228 in your dependencies?