What is CVE-2021-44228?
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.
The record classifies CVE-2021-44228 under weakness classes CWE-20, CWE-400, CWE-502, CWE-917. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 381 affected-product entries are recorded, across 2 vendors, listed below. The identifier was first published 1767 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 10 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - EPSS (FIRST)
- 99.9% probability of exploitation in the next 30 days, higher than 99.9% of all scored CVEs
- CISA KEV
- Listed since 2021-12-10, federal remediation deadline 2021-12-24 — used in known ransomware campaigns
- Threadlinqs priority
- 10/10 — CISA lists it as used in ransomware, which Threadlinqs scores at the maximum
- Published
- 2021-12-10, last modified 2025-10-21
Is CVE-2021-44228 being exploited?
CISA added CVE-2021-44228 to the Known Exploited Vulnerabilities catalog on 2021-12-10, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2021-12-24 under BOD 22-01. CISA flags the vulnerability as one used in known ransomware campaigns. Weaponised exploit code for CVE-2021-44228 is publicly available. 11 public proof-of-concept repositories are tracked for this identifier. A ProjectDiscovery Nuclei detection template exists (http/cves/2021/CVE-2021-44228.yaml). It currently carries a trending score of 50 in the Threadlinqs vulnerability feed.
- fullhunt/log4j-scan (github)
- kozmer/log4j-shell-poc (github)
- christophetd/log4shell-vulnerable-app (github)
- Puliczek/CVE-2021-44228-PoC-log4j-bypass-words (github)
- logpresso/CVE-2021-44228-Scanner (github)
- f0ng/log4j2burpscanner (github)
- mergebase/log4j-detector (github)
- corretto/hotpatch-for-apache-log4j2 (github)
Affected products and versions
- Siemens: 6bk1602-0aa12-0tp0 Firmware, 6bk1602-0aa12-0tp0, 6bk1602-0aa22-0tp0 Firmware, 6bk1602-0aa22-0tp0, 6bk1602-0aa32-0tp0 Firmware, 6bk1602-0aa32-0tp0, 6bk1602-0aa42-0tp0 Firmware, 6bk1602-0aa42-0tp0, 6bk1602-0aa52-0tp0 Firmware, 6bk1602-0aa52-0tp0, Sppa-t3000 Ses3000 Firmware, Sppa-t3000 Ses3000, Capital, Capital 2019.1, Comos, Desigo Cc Advanced Reports 3.0, Desigo Cc Advanced Reports 4.0, Desigo Cc Advanced Reports 4.1, Desigo Cc Advanced Reports 4.2, Desigo Cc Advanced Reports 5.0, Desigo Cc Advanced Reports 5.1, Desigo Cc Info Center 5.0, Desigo Cc Info Center 5.1
- Apache: Log4j, Log4j 2.0
Showing 25 of 381 recorded product entries.
How to fix CVE-2021-44228
Vendor advisory: https://logging.apache.org/log4j/2.x/security.html. Because CVE-2021-44228 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2021-12-24. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2021-44228
5 tracked threats in the Threadlinqs corpus reference CVE-2021-44228, either in the campaign’s CVE list or as an indicator on the campaign record.
- DragonForce Ransomware Attack on RubberMill, Inc. — ~340GB Data Exfiltration Including PII, Credentials, CAD Files with Defense Mil-Spec References — CRITICAL · 2026-09-06
- Chinese-Speaking Operator "Nie" Uses SecFlow AI Orchestration Framework (Claude, Qwen, DeepSeek) and GLUTTON Steganographic Webshell in Multi-Country Espionage Campaign — HIGH · 2026-09-04
- LockBit 5.0 Ransomware Extortion Claim Against US Bank (U.S. Bancorp) — HIGH · 2026-08-21
- Aquatic Panda (Earth Lusca) APT - Log4Shell Exploitation and Multi-Platform Backdoor Campaigns Targeting 17 Countries — CRITICAL · 2026-06-28
- APT41/Silver Dragon Expanding Enterprise Attack Surface — Google Drive C2, AppDomain Hijacking, Cloud/Supply Chain Targeting — HIGH · 2026-03-27
Sources
Enriched from CVE.org, FIRST EPSS, CISA KEV, public proof-of-concept repositories, ProjectDiscovery Nuclei. Last verified by Threadlinqs on .
Vendor advisory and patch
- tools.cisco.com — vendor advisory
- debian.org — vendor advisory
- lists.fedoraproject.org — vendor advisory
- msrc-blog.microsoft.com — vendor advisory
Third-party advisory
Mailing list and disclosure
- openwall.com — mailing list
- openwall.com — mailing list (2)
- openwall.com — mailing list (3)
- lists.debian.org — mailing list
- openwall.com — mailing list (2)
Other references
Showing 15 of 28 recorded references.