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CVE-2021-45046

9.0 · CRITICALActively Exploited

It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations.

Published Dec 14, 2021CWE-917EPSS 99.98%

Overview

CVE-2021-45046 is a critical-severity vulnerability. It was published on December 14, 2021 and has a CVSS 3.1 base score of 9.0 (CRITICAL). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

This vulnerability has a CVSS 3.1 base score of 9.0, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refwww.openwall.com/lists/oss-security/2021/12/14/4Refwww.openwall.com/lists/oss-security/2021/12/15/3Refwww.openwall.com/lists/oss-security/2021/12/18/1Refcert-portal.siemens.com/productcert/pdf/ssa-397453.pdfRefcert-portal.siemens.com/productcert/pdf/ssa-479842.pdfRefcert-portal.siemens.com/productcert/pdf/ssa-661247.pdfRefcert-portal.siemens.com/productcert/pdf/ssa-714170.pdfReflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/Reflogging.apache.org/log4j/2.x/security.html

How CyberStrike helps

Frequently asked questions

What is CVE-2021-45046?

CVE-2021-45046 is a critical-severity vulnerability. It was published on December 14, 2021 and has a CVSS 3.1 base score of 9.0 (CRITICAL). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

How severe is CVE-2021-45046?

This vulnerability has a CVSS 3.1 base score of 9.0, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-45046?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-45046?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-45046 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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