{"id":"CVE-2021-45046","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-45046","generatedAt":"2026-10-31T14:05:36.762Z","title":"Apache Log4j2 Deserialization of Untrusted Data Vulnerability","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.","published":"2021-12-14T19:15:08.000Z","lastModified":"2026-06-17T04:13:06.000Z","status":"Analyzed","sourceIdentifier":"security@apache.org","cvss":{"version":"3.1","score":9,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H"},"cwe":["CWE-917"],"affected":["apache/log4j","cvat/computer vision annotation tool","intel/audio development kit","intel/datacenter manager","intel/genomics kernel library","intel/oneapi","intel/secure device onboard","intel/sensor solution firmware development kit","intel/system debugger","intel/system studio","siemens/sppa-t3000 ses3000 firmware","siemens/captial","siemens/comos","siemens/desigo cc advanced reports","siemens/desigo cc info center","siemens/e-car operation center","siemens/energy engage","siemens/energyip","siemens/energyip prepay","siemens/gma-manager","siemens/head-end system universal device integration system","siemens/industrial edge management","siemens/industrial edge management hub","siemens/logo\\! soft comfort","siemens/mendix","siemens/mindsphere","siemens/navigator","siemens/nx","siemens/opcenter intelligence","siemens/operation scheduler","siemens/sentron powermanager","siemens/siguard dsa","siemens/sipass integrated","siemens/siveillance command","siemens/siveillance control pro","siemens/siveillance identity","siemens/siveillance vantage","siemens/siveillance viewpoint","siemens/solid edge cam pro","siemens/solid edge harness design","siemens/spectrum power 4","siemens/spectrum power 7","siemens/teamcenter","siemens/tracealertserverplus","siemens/vesys","siemens/xpedition enterprise","siemens/xpedition package integrator","debian/debian linux","sonicwall/email security","fedoraproject/fedora","siemens/6bk1602-0aa12-0tp0 firmware","siemens/6bk1602-0aa22-0tp0 firmware","siemens/6bk1602-0aa32-0tp0 firmware","siemens/6bk1602-0aa42-0tp0 firmware","siemens/6bk1602-0aa52-0tp0 firmware"],"epss":{"score":0.99977,"percentile":0.9998,"date":"2026-10-30","history":[]},"kev":{"listed":true,"dateAdded":"2023-05-01","dueDate":"2023-05-22","knownRansomwareCampaignUse":"Known","notes":"Apply updates per vendor instructions.\nhttps://logging.apache.org/log4j/2.x/security.html; https://nvd.nist.gov/vuln/detail/CVE-2021-45046"},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 22 May 2023). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"http://www.openwall.com/lists/oss-security/2021/12/14/4","tags":["Mailing List","Mitigation","Third Party Advisory"],"source":"security@apache.org"},{"url":"http://www.openwall.com/lists/oss-security/2021/12/15/3","tags":["Mailing List","Third Party Advisory"],"source":"security@apache.org"},{"url":"http://www.openwall.com/lists/oss-security/2021/12/18/1","tags":["Mailing List","Third Party Advisory"],"source":"security@apache.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/","tags":["Mailing List","Release Notes"],"source":"security@apache.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/","tags":["Mailing List","Release Notes"],"source":"security@apache.org"},{"url":"https://logging.apache.org/log4j/2.x/security.html","tags":["Mitigation","Release Notes","Vendor Advisory"],"source":"security@apache.org"},{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://security.gentoo.org/glsa/202310-16","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-44228","tags":["Not Applicable"],"source":"security@apache.org"},{"url":"https://www.debian.org/security/2021/dsa-5022","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.kb.cert.org/vuls/id/930724","tags":["Third Party Advisory","US Government Resource"],"source":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/alert-cve-2021-44228.html","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","tags":["Patch","Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpujul2022.html","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"http://www.openwall.com/lists/oss-security/2021/12/14/4","tags":["Mailing List","Mitigation","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2021/12/15/3","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2021/12/18/1","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/","tags":["Mailing List","Release Notes"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/","tags":["Mailing List","Release Notes"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://logging.apache.org/log4j/2.x/security.html","tags":["Mitigation","Release Notes","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202310-16","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-44228","tags":["Not Applicable"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2021/dsa-5022","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.kb.cert.org/vuls/id/930724","tags":["Third Party Advisory","US Government Resource"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/alert-cve-2021-44228.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujul2022.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-45046","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-45046","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}