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CVE-2021-45046

Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack

Basic Information

CVE State
PUBLISHED
Reserved Date
December 14, 2021
Published Date
December 14, 2021
Last Updated
February 13, 2025
Vendor
Apache Software Foundation
Product
Apache Log4j
Description
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 Scores

CVSS v3.1

9.0 - CRITICAL

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

SSVC Information

Exploitation
active
Technical Impact
total

Exploit Status

Exploited in the Wild
Yes (added 2023-05-01 00:00:00 UTC) Source
Proof of Concept Available
Yes (added 2021-12-15 16:28:11 UTC) Source
Used in Malware
Yes (added 2023-05-01 00:00:00 UTC) Source

References

https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032 https://www.oracle.com/security-alerts/alert-cve-2021-44228.html https://www.cve.org/CVERecord?id=CVE-2021-44228 http://www.openwall.com/lists/oss-security/2021/12/14/4 https://logging.apache.org/log4j/2.x/security.html https://www.kb.cert.org/vuls/id/930724 https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd http://www.openwall.com/lists/oss-security/2021/12/15/3 https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf https://www.debian.org/security/2021/dsa-5022 http://www.openwall.com/lists/oss-security/2021/12/18/1 https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/ https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/ https://www.oracle.com/security-alerts/cpujan2022.html https://www.oracle.com/security-alerts/cpuapr2022.html https://www.oracle.com/security-alerts/cpujul2022.html https://security.gentoo.org/glsa/202310-16

Known Exploited Vulnerability Information

Source Added Date
CISA 2023-05-01 00:00:00 UTC

Scanner Integrations

Scanner URL Date Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-45046.yaml 2025-04-26 00:00:00 UTC

Potential Proof of Concepts

Warning: These PoCs have not been tested and could contain malware. Use at your own risk.

tejas-nagchandi/CVE-2021-45046

Type: github • Created: 2021-12-15 16:28:11 UTC • Stars: 0

Replicating CVE-2021-45046

BobTheShoplifter/CVE-2021-45046-Info

Type: github • Created: 2021-12-15 09:01:37 UTC • Stars: 4

Oh no another one

cckuailong/Log4j_CVE-2021-45046

Type: github • Created: 2021-12-15 05:48:53 UTC • Stars: 20

Log4j 2.15.0 Privilege Escalation -- CVE-2021-45046