CVE-2021-45046: Apache Log4j2 Deserialization of Untrusted Data Vulnerability
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, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data…
Published Dec 14, 2021 · Updated Jun 17, 2026
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Advisory details
From the National Vulnerability Database. This product uses the NVD API but is not endorsed or certified by the NVD.
It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${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.
References
- https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-714170.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://logging.apache.org/log4j/2.x/security.html
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032
- https://security.gentoo.org/glsa/202310-16
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd
- https://www.cve.org/CVERecord?id=CVE-2021-44228
- https://www.debian.org/security/2021/dsa-5022
- https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html
- https://www.kb.cert.org/vuls/id/930724
- https://www.oracle.com/security-alerts/alert-cve-2021-44228.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpujul2022.html
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-45046
How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology
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