CVE-2021-45105

CRITICALNVD 5.99.0▲
EchelonGraph scoreMEDIUM confidence

Score elevated to 9.0 because EPSS predicts 100% probability of exploitation within the next 30 days (99th percentile of EPSS-scored CVEs). NVD baseline CVSS 5.9 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction (continuous uplift above 30%)
Sources: epss, nvd
Elevated
9.0EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 100%
CISA-KEV: Not listedEPSS PROB: 100%CVSS: 5.9Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue was fixed in Log4j 2.17.0, 2.12.3, and 2.3.1.

CVSS v3
5.9
EG Score
9.0CRITICALmedium confidence
EG Risk
80
EG Risk 80/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
100%
EPSS %ILE
99th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

December 18, 2021

Last Modified

August 25, 2026

Advisory Details (9)

Auto-updated Aug 25, 2026
🔬 Proof of concept available. Patch available. Sources: cert.
cert

VU#930724 - Apache Log4j allows insecure JNDI lookups

https://www.kb.cert.org/vuls/id/930724
generic

[SECURITY] [DSA 5024-1] apache-log4j2 security update

https://www.debian.org/security/2021/dsa-5024
generic🟡 PoC Available

Vulnerabilities in Apache Log4j Library Affecting Cisco Products: December 2021

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20211218-0001/
generic

Security Advisory

https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032
genericMentions a patch (unverified)

Security :: Apache Logging Services

https://logging.apache.org/log4j/2.x/security.html
generic
https://cert-portal.siemens.com/productcert/pdf/ssa-501673.pdf
generic
https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf
generic

oss-security - CVE-2021-45105: Apache Log4j2 does not always protect from infinite recursion in lookup evaluation

http://www.openwall.com/lists/oss-security/2021/12/19/1

Vendor Advisories for CVE-2021-45105(19)

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

Patch Availability(16)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntuliblog4j2-java (2.17.0-0.21.10.1) @ impish2026-08-25ubuntu
ubuntuliblog4j2-java (2.17.1-0.21.10.1) @ impish2026-08-25ubuntu
redhatrh-sso7-keycloak-0:15.0.6-1.redhat_00001.1.el8sso2022-04-20redhat
redhatlog4j-api2022-04-20redhat
redhatrh-sso7-keycloak-0:15.0.6-1.redhat_00001.1.el7sso2022-04-20redhat
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
redhatorg.apache.logging.log4j/log4j-api:2.17.1.redhat-000012022-04-11redhat
redhatlog4j-core2022-01-20redhat
redhatpatch2022-01-20redhat
redhatpatch2022-01-20redhat
redhatopenshift4/ose-logging-elasticsearch6:v4.6.0-202112201736.p0.gce7f68c.assembly.stream2022-01-12redhat
redhatopenshift-logging/elasticsearch6-rhel8:v5.0.11-22022-01-10redhat
redhatopenshift-logging/elasticsearch6-rhel8:v6.8.1-822022-01-10redhat
redhatopenshift-logging/elasticsearch6-rhel8:v6.8.1-842022-01-10redhat
redhatopenshift-logging/elasticsearch6-rhel8:v6.8.1-832022-01-10redhat

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

(8 across 7 ecosystems)
Maven(2)
PackageVulnerable rangeFix by version rangeDependents
org.apache.logging.log4j:log4j-core2.0 ... 2.3 (19 versions)
  • 2.4.0 up to 2.12.3: fixed in 2.12.3
  • 2.13.0 up to 2.17.0: fixed in 2.17.0
  • every version up to 2.3.1: fixed in 2.3.1
—
org.ops4j.pax.logging:pax-logging-log4j22.0.0 ... 2.0.9 (13 versions)
  • 1.8.0 up to 1.9.2: fixed in 1.9.2
  • 1.10.0 up to 1.10.9: fixed in 1.10.9
  • 1.11.0 up to 1.11.12: fixed in 1.11.12
  • 2.0.0 up to 2.0.13: fixed in 2.0.13
—
Debian:10(1)
PackageVulnerable rangeFix by version rangeDependents
apache-log4j22.11.1-2 ... 2.16.0-1~deb11u1 (9 versions)
  • every version up to 2.17.0-1~deb10u1: fixed in 2.17.0-1~deb10u1
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
apache-log4j22.13.3-1 ... 2.17.0-1~deb10u1 (8 versions)
  • every version up to 2.17.0-1~deb11u1: fixed in 2.17.0-1~deb11u1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
apache-log4j2—
  • every version up to 2.17.0-1: fixed in 2.17.0-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
apache-log4j2—
  • every version up to 2.17.0-1: fixed in 2.17.0-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
apache-log4j2—
  • every version up to 2.17.0-1: fixed in 2.17.0-1
—
Debian:9(1)
PackageVulnerable rangeFix by version rangeDependents
apache-log4j22.10.0-1 ... 2.8.2-2 (9 versions)
  • every version up to 2.12.3-0+deb9u1: fixed in 2.12.3-0+deb9u1
—

Weakness Classification(2)

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

Additional Vendor Advisories

(2)

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.

Data Freshness Timeline

(refreshed 0× in last 7d / 3× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-02 17:40 UTCOSV refresh
  2. 2026-09-30 15:44 UTCEG score recompute
  3. 2026-09-13 14:54 UTCOSV refresh
  4. 2026-08-25 16:34 UTCEG score recompute
  5. 2026-08-25 16:34 UTCVendor advisory
  6. 2026-08-24 07:57 UTCOSV refresh
  7. 2026-08-16 02:11 UTCEPSS rescore
  8. 2026-08-08 04:19 UTCOSV refresh
  9. 2026-07-23 02:05 UTCEG score recompute
  10. 2026-07-22 21:21 UTCEG score recompute▲ 3.10
  11. 2026-07-22 21:21 UTCVendor advisory
  12. 2026-07-18 05:29 UTCOSV refresh
  13. 2026-06-30 02:00 UTCOSV refresh
  14. 2026-06-15 17:46 UTCEPSS rescore
  15. 2026-06-13 22:58 UTCEPSS rescore
  16. 2026-06-13 22:58 UTCEPSS rescore
  17. 2026-06-12 23:10 UTCEPSS rescore
  18. 2026-06-12 14:40 UTCOSV refresh
  19. 2026-06-11 13:58 UTCEPSS rescore
  20. 2026-06-11 13:58 UTCEPSS rescore
  21. 2026-06-10 22:16 UTCEPSS rescore
  22. 2026-06-10 22:16 UTCEPSS rescore
  23. 2026-06-10 13:20 UTCEPSS rescore
  24. 2026-06-08 14:15 UTCEPSS rescore
  25. 2026-06-08 14:15 UTCEPSS rescore
Show 20 more
  1. 2026-06-07 15:23 UTCEPSS rescore
  2. 2026-06-07 15:23 UTCEPSS rescore
  3. 2026-06-05 22:45 UTCEPSS rescore
  4. 2026-06-05 06:09 UTCEPSS rescore
  5. 2026-06-05 06:09 UTCEPSS rescore
  6. 2026-06-04 13:10 UTCEPSS rescore
  7. 2026-06-04 13:10 UTCEPSS rescore
  8. 2026-06-02 20:11 UTCEPSS rescore
  9. 2026-06-02 20:11 UTCEPSS rescore
  10. 2026-06-01 13:50 UTCEPSS rescore
  11. 2026-06-01 13:50 UTCEPSS rescore
  12. 2026-05-31 00:15 UTCEPSS rescore
  13. 2026-05-31 00:15 UTCEPSS rescore
  14. 2026-05-29 13:42 UTCEPSS rescore
  15. 2026-05-28 13:43 UTCEPSS rescore
  16. 2026-05-28 13:43 UTCEPSS rescore
  17. 2026-05-27 13:39 UTCEPSS rescore
  18. 2026-05-27 13:39 UTCEPSS rescore
  19. 2026-05-26 06:06 UTCEG score recompute
  20. 2026-05-26 06:06 UTCVendor advisory

Publicly available exploits

(2 references)

Working exploit code is in the public domain (2 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCiAmSOScArEd/log4j2_dos_exploit
    First seen Dec 20, 2021

    log4j2 dos exploit,CVE-2021-45105 exploit,Denial of Service poc

    Open source ↗
  • GitHub PoCcckuailong/Log4j_dos_CVE-2021-45105
    First seen Dec 18, 2021

    Log4j_dos_CVE-2021-45105

    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

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-45105?
CVE-2021-45105 is a critical vulnerability published on December 18, 2021. Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue…
When was CVE-2021-45105 disclosed?
CVE-2021-45105 was first published on December 18, 2021, with the most recent update on August 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-45105 actively exploited?
CVE-2021-45105 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 100% probability of exploitation in the next 30 days (99th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-45105?
CVE-2021-45105 has a CVSS v3 base score of 5.9 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0 (CRITICAL).
How do I remediate CVE-2021-45105?
A fix for CVE-2021-45105 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-45105 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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