{"cve":{"cve_id":"CVE-2021-45046","is_kev":true,"kev_date_added":"2023-05-01","kev_vendor_project":"Apache","kev_product":"Log4j2","kev_vulnerability_name":"Apache Log4j2 Deserialization of Untrusted Data Vulnerability","kev_short_description":"Apache Log4j2 contains a deserialization of untrusted data vulnerability due to the incomplete fix of CVE-2021-44228, where the Thread Context Lookup Pattern is vulnerable to remote code execution in certain non-default configurations.","kev_required_action":"Apply updates per vendor instructions.","kev_due_date":"2023-05-22","kev_known_ransomware":true,"kev_notes":"https://logging.apache.org/log4j/2.x/security.html; https://nvd.nist.gov/vuln/detail/CVE-2021-45046","kev_cwes":["CWE-917"],"epss_score":0.99977,"epss_percentile":0.9998,"epss_as_of":"2026-06-23","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_at":"2021-12-14T16:55:09Z","last_modified_at":null,"cvss_v3_score":9.0,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H","cvss_v3_severity":"CRITICAL","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":"active","ssvc_automatable":false,"ssvc_technical_impact":"total","cwes":["CWE-917"],"nvd_references":["https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032","https://www.oracle.com/security-alerts/alert-cve-2021-44228.html","https://www.cve.org/CVERecord?id=CVE-2021-44228","http://www.openwall.com/lists/oss-security/2021/12/14/4","https://logging.apache.org/log4j/2.x/security.html","https://www.kb.cert.org/vuls/id/930724","https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf","https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html","https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd","http://www.openwall.com/lists/oss-security/2021/12/15/3","https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf","https://www.debian.org/security/2021/dsa-5022","http://www.openwall.com/lists/oss-security/2021/12/18/1","https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf","https://cert-portal.siemens.com/productcert/pdf/ssa-479842.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://www.oracle.com/security-alerts/cpujan2022.html","https://www.oracle.com/security-alerts/cpuapr2022.html","https://www.oracle.com/security-alerts/cpujul2022.html","https://security.gentoo.org/glsa/202310-16"],"vuln_status":null,"trending_score":0.6099586,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:31.350578Z","updated_at":"2026-06-29T02:30:27.550645Z"},"effective_severity":"CRITICAL","badges":["kev","ransomware","poc","epss"],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"H","value_label":"High"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"C","value_label":"Changed"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"apache-software-foundation","vendor_name":"Apache Software Foundation","product_slug":"apache-log4j","product_name":"Apache Log4j","version_start":"Apache Log4j2","version_start_inclusive":true,"version_end":"2.16.0","version_end_inclusive":false,"cpe23_uri":"cve5:apache-software-foundation:apache-log4j:Apache Log4j2:2.16.0"}],"exploit_refs":[{"source":"nuclei","kind":"nuclei","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-45046.yaml","title":"Apache Log4j2 - Remote Code Injection","author":"ImNightmaree","disclosed_at":null},{"source":"nuclei","kind":"nuclei","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/dast/cves/2021/CVE-2021-45046.yaml","title":"Apache Log4j2 - Remote Code Injection","author":"princechaddha","disclosed_at":null}],"news":[],"references":[{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://www.oracle.com/security-alerts/alert-cve-2021-44228.html","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-44228","source_type":"CONFIRM","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2021/12/14/4","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://logging.apache.org/log4j/2.x/security.html","source_type":"MISC","tags":[]},{"url":"https://www.kb.cert.org/vuls/id/930724","source_type":"MISC","tags":[]},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf","source_type":"MISC","tags":[]},{"url":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html","source_type":"MISC","tags":[]},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2021/12/15/3","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf","source_type":"MISC","tags":[]},{"url":"https://www.debian.org/security/2021/dsa-5022","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2021/12/18/1","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf","source_type":"MISC","tags":[]},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf","source_type":"MISC","tags":[]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://www.oracle.com/security-alerts/cpujul2022.html","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://security.gentoo.org/glsa/202310-16","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2021-12-14T16:55:09Z","label":"CVE published","source":null},{"type":"cisa_reported","at":"2023-05-01T00:00:00Z","label":"Added to CISA KEV catalog","source":"kev"},{"type":"poc_available","at":"2026-06-24T00:29:48.638073Z","label":"Public PoC available","source":"nuclei"},{"type":"ssvc_changed","at":"2026-06-24T00:31:47.654584Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-24T00:31:47.654584Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-24T00:31:47.654584Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-06-24T00:31:47.654584Z","label":"CVSS score revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-06-24T00:31:47.654584Z","label":"CVSS score revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-06-24T00:31:47.654584Z","label":"CVSS score revised","source":"vulnrichment"}]}