CVE-2021-45105

MEDIUMNVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.9 under NVD CVSS v3. EPSS exploit probability: 74.5%, top 1% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
5.9
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 100%
CISA-KEV: Not listedEPSS: 100%CVSS: 5.9Exploit: NoneExposed: 0

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
5.9(medium)
EPSS
100.0%
KEV
Not listed

Published

December 18, 2021

Last Modified

May 29, 2026

References (26)

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(15)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuliblog4j2-java (2.17.1-0.21.10.1) @ impish2026-05-26ubuntu
ubuntuliblog4j2-java-doc (2.17.0-0.20.04.1) @ focal2026-05-26ubuntu
redhatlog4j-api2022-04-20redhat
redhatrh-sso7-keycloak-0:15.0.6-1.redhat_00001.1.el7sso2022-04-20redhat
redhatrh-sso7-keycloak-0:15.0.6-1.redhat_00001.1.el8sso2022-04-20redhat
redhateap7-log4j-0:2.17.1-1.redhat_00001.1.el7eap2022-04-11redhat
redhatlog4j-core2022-04-11redhat
redhateap7-log4j-0:2.17.1-1.redhat_00001.1.el8eap2022-04-11redhat
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

(2 across 1 ecosystem)
Maven(2)
PackageVulnerable rangeFixed inDependents
org.apache.logging.log4j:log4j-core2.0 ... 2.3 (19 versions)2.3.1—
org.ops4j.pax.logging:pax-logging-log4j22.0.0 ... 2.0.9 (13 versions)2.0.13—

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

Frequently asked(5)

What is CVE-2021-45105?
CVE-2021-45105 is a medium 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 in the National Vulnerability Database on December 18, 2021, with the most recent update on May 29, 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 100.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-45105?
CVE-2021-45105 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2021-45105?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-45105, 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

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