# CVE-2021-45046

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.

- Page: https://www.vulneraibility.com/cve/CVE-2021-45046
- CVSS: 9.0
- Known exploited: yes, in CISA KEV since 2023-05-01; CISA due date 2023-05-22; known ransomware use
- EPSS: 99.98% (percentile 100.0)
- Unvetted proof-of-concept code on GitHub: 1 Metasploit module · 11 GitHub proofs of concept · 1 Nuclei template (first 2021-12-15)
- CISA SSVC: exploitation active, automatable no, technical impact total (assessed 2025-02-04)
- Weakness: CWE-917
- Also known as: GHSA-7rjr-3q55-vv33
- Published: 2021-12-14

## Affected versions

- Apache Software Foundation Apache Log4j: affected >= Apache Log4j2 and < 2.16.0

A version outside these ranges is not a statement that it is unaffected.

## References

- [other] https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032
- [other] https://www.oracle.com/security-alerts/alert-cve-2021-44228.html
- [other] https://www.cve.org/CVERecord?id=CVE-2021-44228
- [other] http://www.openwall.com/lists/oss-security/2021/12/14/4
- [other] https://logging.apache.org/log4j/2.x/security.html
- [advisory] https://www.kb.cert.org/vuls/id/930724
- [other] https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf
- [other] https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html
- [advisory] https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd
- [other] http://www.openwall.com/lists/oss-security/2021/12/15/3
- [other] https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf
- [advisory] https://www.debian.org/security/2021/dsa-5022
- [other] http://www.openwall.com/lists/oss-security/2021/12/18/1
- [other] https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf
- [other] https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf
- [advisory] https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/
- [advisory] https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/
- [other] https://www.oracle.com/security-alerts/cpujan2022.html
- [other] https://www.oracle.com/security-alerts/cpuapr2022.html
- [other] https://www.oracle.com/security-alerts/cpujul2022.html
- [other] https://security.gentoo.org/glsa/202310-16
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-45046

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.