CVE-2021-45046

CRITICALNVD 9.09.0—
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2023-05-01), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 9.0 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, nvd
Exploited in the wild
9.0
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 100%CVSS: 9.0Exploit: NoneExposed: 0

A fix is available — apply it.

It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.

CVSS v3
9.0
EG Score
9.0(high)
EPSS
100.0%
KEV
⚠ Exploited

Published

December 14, 2021

Last Modified

October 27, 2025

Advisory Details (6)

Auto-updated Jun 2, 2026
No patch confirmed yet.
generic

Security :: Apache Logging Services

https://logging.apache.org/log4j/2.x/security.html
generic

[SECURITY] Fedora 35 Update: log4j-2.17.0-1.fc35 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/
generic

[SECURITY] Fedora 34 Update: log4j-2.17.0-1.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/
generic

oss-security - Re: CVE-2021-45046: Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack

http://www.openwall.com/lists/oss-security/2021/12/18/1
generic

oss-security - Re: CVE-2021-45046: Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack

http://www.openwall.com/lists/oss-security/2021/12/15/3
generic

oss-security - CVE-2021-45046: Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack

http://www.openwall.com/lists/oss-security/2021/12/14/4

Vendor Advisories for CVE-2021-45046(20)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(18)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuliblog4j2-java (2.16.0-0.21.10.1) @ impish2026-07-12ubuntu
redhateap7-wildfly-0:7.1.9-2.GA_redhat_00002.1.ep7.el72025-02-24redhat
redhateap7-wildfly-0:7.3.12-3.GA_redhat_00002.1.el7eap2025-02-24redhat
redhatlog4j-core2022-04-11redhat
redhateap7-log4j-0:2.17.1-1.redhat_00001.1.el8eap2022-04-11redhat
redhateap7-log4j-0:2.17.1-1.redhat_00001.1.el7eap2022-04-11redhat
redhatpatch2022-01-20redhat
redhatpatch2022-01-13redhat
redhatopenshift4/ose-metering-hive:v4.6.0-202112140546.p0.g8b9da97.assembly.stream2021-12-16redhat
redhatopenshift4/ose-metering-presto:v4.6.0-202112150545.p0.g190688a.assembly.art35952021-12-16redhat
redhatopenshift4/ose-metering-presto:v4.7.0-202112150631.p0.gd502108.assembly.4.7.402021-12-16redhat
redhatopenshift4/ose-metering-presto:v4.8.0-202112150431.p0.g4b934ae.assembly.art35992021-12-15redhat
redhatopenshift3/ose-logging-elasticsearch5:v3.11.570-2.gd1198202021-12-14redhat
redhatopenshift-logging/elasticsearch6-rhel8:v6.8.1-662021-12-14redhat
redhatopenshift4/ose-metering-hive:v4.8.0-202112132154.p0.g57dd03a.assembly.stream2021-12-14redhat
redhatopenshift-logging/elasticsearch6-rhel8:v6.8.1-652021-12-14redhat
redhatopenshift-logging/elasticsearch6-rhel8:v6.8.1-672021-12-14redhat
redhatopenshift-logging/elasticsearch6-rhel8:v5.0.10-12021-12-14redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(2 across 1 ecosystem)
Maven(2)
PackageVulnerable rangeFixed inDependents
org.apache.logging.log4j:log4j-core2.0 ... 2.9.1 (39 versions)2.12.2—
org.ops4j.pax.logging:pax-logging-log4j22.0.0 ... 2.0.9 (12 versions)2.0.12—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(3)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Publicly available exploits

(7 references)

Working exploit code is in the public domain (1 Metasploit module) (5 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCifconfig-me/Log4Shell-Payloads
    First seen Jul 23, 2025

    Log4Shell / Log4J Payload - CVE-2021-45046 and CVE-2022-42889

    Open source ↗
  • GitHub PoClijiejie/log4j2_vul_local_scanner
    First seen Dec 20, 2021

    Log4j 漏洞本地检测脚本。 Scan all java processes on your host to check whether it's affected by log4j2 remote code execution vulnerability (CVE-2021-45046)

    Open source ↗
  • GitHub PoCmergebase/log4j-samples
    First seen Dec 16, 2021

    Public testing data. Samples of log4j library versions to help log4j scanners / detectors improve their accuracy for detecting CVE-2021-45046 and CVE-2021-44228. TAG_TESTING, OWNER_KEN, DC_PUBLIC

    Open source ↗
  • GitHub PoCcckuailong/Log4j_CVE-2021-45046
    First seen Dec 15, 2021

    Log4j 2.15.0 Privilege Escalation -- CVE-2021-45046

    Open source ↗
  • GitHub PoCBobTheShoplifter/CVE-2021-45046-Info
    First seen Dec 15, 2021

    Oh no another one

    Open source ↗
  • Metasploitauxiliary/scanner/http/log4shell_scanner✓ verified
    First seen Dec 9, 2021

    Log4Shell HTTP Scanner

    Open source ↗
  • Nucleihttp/cves/2021/CVE-2021-45046.yaml
    First seen Jan 1, 2021

    Apache Log4j2 - Remote Code Injection

    Open source ↗

Past incidents using this CVE

(1)

This CVE was central to one or more publicly-documented breaches. Each card links to authoritative reporting at the time of the incident.

  • Log4Shell (Apache Log4j)Dec 2021

    JNDI lookup injection in Log4j, a ubiquitous Java logging library. Pre-auth unauthenticated RCE; Apache Foundation called it the worst vulnerability in a decade. Active exploitation continues 3+ years later.

    Source: Wired

Frequently asked(6)

What is CVE-2021-45046?
CVE-2021-45046 is a critical vulnerability published on December 14, 2021. It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context…
When was CVE-2021-45046 disclosed?
CVE-2021-45046 was first published in the National Vulnerability Database on December 14, 2021, with the most recent update on October 27, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-45046 actively exploited?
Yes. CISA added CVE-2021-45046 to the Known Exploited Vulnerabilities catalog on May 1, 2023, affecting Apache Log4j2. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-45046?
CVE-2021-45046 has a CVSS v3 base score of 9.0 (NVD).
Which products are affected by CVE-2021-45046?
CVE-2021-45046 affects Apache Log4j2. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2021-45046?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-45046, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-45046

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