# CVE-2021-45046

## Summary

- **CVE ID:** CVE-2021-45046
- **Severity:** CRITICAL
- **CVSS Score:** 9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H)
- **CWE:** CWE-917
- **Published:** Dec 14, 2021
- **Last Modified:** Sep 16, 2026

## 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.

## Affected Products

- Apache Software Foundation — Apache Log4j (Apache Log4j2)

## References

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

## Exploitation Prediction (EPSS)

- **EPSS Score:** 94.34%
- **EPSS Percentile:** 100.0

## Known Exploited Vulnerabilities (KEV)

- **Date Added:** May 1, 2023
- **Due Date:** May 22, 2023

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._