CVE-2021-45046
Apache Software Foundation Apache Log4j
Published 14 Dec 2021 · updated 17 Jun 2026 · Analyzed
Exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on 1 May 2023, with a remediation deadline of 22 May 2023 for US federal agencies. It has been used in ransomware campaigns.
Required action: Apply updates per vendor instructions.
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.
References
- www.openwall.com/lists/oss-security/2021/12/14/4 · Mailing List, Mitigation, Third Party Advisory
- www.openwall.com/lists/oss-security/2021/12/15/3 · Mailing List, Third Party Advisory
- www.openwall.com/lists/oss-security/2021/12/18/1 · Mailing List, Third Party Advisory
- cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf · Third Party Advisory
- cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf · Third Party Advisory
- cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf · Third Party Advisory
- cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf · Third Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/ · Mailing List, Release Notes
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/ · Mailing List, Release Notes
- logging.apache.org/log4j/2.x/security.html · Mitigation, Release Notes, Vendor Advisory
- psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032 · Third Party Advisory
- security.gentoo.org/glsa/202310-16 · Third Party Advisory
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd · Third Party Advisory
- www.cve.org/CVERecord?id=CVE-2021-44228 · Not Applicable
- www.debian.org/security/2021/dsa-5022 · Third Party Advisory
- www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html · Third Party Advisory
- www.kb.cert.org/vuls/id/930724 · Third Party Advisory, US Government Resource
- www.oracle.com/security-alerts/alert-cve-2021-44228.html · Third Party Advisory
- www.oracle.com/security-alerts/cpuapr2022.html · Third Party Advisory
- www.oracle.com/security-alerts/cpujan2022.html · Patch, Third Party Advisory
- www.oracle.com/security-alerts/cpujul2022.html · Third Party Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-45046 · US Government Resource