{
  "id": "CVE-2021-45046",
  "url": "https://spydr.io/cve/CVE-2021-45046",
  "published": "2021-12-14T19:15:07.733Z",
  "modified": "2026-06-17T04:13:05.570Z",
  "score": 9,
  "severity": "critical",
  "cvss_version": "3.1",
  "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H",
  "score_source": "NVD",
  "epss": 0.99977,
  "epss_percentile": 0.9998,
  "exploited": true,
  "kev": {
    "added": "2023-05-01",
    "due": "2023-05-22",
    "action": "Apply updates per vendor instructions.",
    "ransomware": "Known",
    "name": "Apache Log4j2 Deserialization of Untrusted Data Vulnerability",
    "notes": "https://logging.apache.org/log4j/2.x/security.html; https://nvd.nist.gov/vuln/detail/CVE-2021-45046"
  },
  "ssvc_exploitation": "active",
  "vendors": [
    "Apache Software Foundation"
  ],
  "products": [
    "Apache Software Foundation Apache Log4j"
  ],
  "cwes": [
    "CWE-917"
  ],
  "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.",
  "status": "Analyzed",
  "score_type": "Primary",
  "scores": {
    "cvss_v40": null,
    "cvss_v31": 9,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/12/14/4",
      "tags": [
        "Mailing List",
        "Mitigation",
        "Third Party Advisory"
      ]
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/12/15/3",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ]
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/12/18/1",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/",
      "tags": [
        "Mailing List",
        "Release Notes"
      ]
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/",
      "tags": [
        "Mailing List",
        "Release Notes"
      ]
    },
    {
      "url": "https://logging.apache.org/log4j/2.x/security.html",
      "tags": [
        "Mitigation",
        "Release Notes",
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://security.gentoo.org/glsa/202310-16",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-44228",
      "tags": [
        "Not Applicable"
      ]
    },
    {
      "url": "https://www.debian.org/security/2021/dsa-5022",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://www.kb.cert.org/vuls/id/930724",
      "tags": [
        "Third Party Advisory",
        "US Government Resource"
      ]
    },
    {
      "url": "https://www.oracle.com/security-alerts/alert-cve-2021-44228.html",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://www.oracle.com/security-alerts/cpuapr2022.html",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://www.oracle.com/security-alerts/cpujan2022.html",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://www.oracle.com/security-alerts/cpujul2022.html",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-45046",
      "tags": [
        "US Government Resource"
      ]
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2021-45046",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}