{
  "crds_version": "0.1",
  "kind": "base",
  "id": "crds:cve-2021-45105",
  "revision": 1,
  "title": "Log4j — Denial of Service via Self-Referential Lookup",
  "summary": "A later Log4j flaw: a self-referential lookup in context data recurses until the thread dies, so an attacker who can shape logged context can stop the application.",
  "source_type": "cve",
  "severity": "medium",
  "cvss": {
    "score": 5.9,
    "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
    "version": "3.1"
  },
  "epss": 0.99999,
  "exploitation": {
    "known_exploited": false,
    "exploit_available": false,
    "attack_complexity": "high",
    "prerequisites": "Control over a value that reaches thread context data"
  },
  "remediation": {
    "patch_available": true
  },
  "mitre_attack": [
    "T1499"
  ],
  "kill_chain": "impact",
  "recommended_action": "Upgrade Log4j past 2.16.0, and keep attacker-controlled values out of thread context data.",
  "confidence": "medium",
  "provenance": [
    {
      "fields": [
        "cvss",
        "exploitation.attack_complexity",
        "exploitation.exploit_available",
        "references",
        "published_at"
      ],
      "source": "https://nvd.nist.gov/vuln/detail/CVE-2021-45105",
      "retrieved_at": "2026-08-07T16:48:34.775Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
        "epss"
      ],
      "source": "https://api.first.org/data/v1/epss?cve=CVE-2021-45105",
      "retrieved_at": "2026-08-07T16:48:34.775Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
        "title",
        "summary",
        "severity",
        "remediation",
        "mitre_attack",
        "kill_chain",
        "recommended_action",
        "confidence",
        "tags",
        "exploitation.prerequisites"
      ],
      "source": "https://nvd.nist.gov/vuln/detail/CVE-2021-45105",
      "retrieved_at": "2026-08-07T16:48:34.775Z",
      "confidence": "high",
      "extractor": "claude-code"
    }
  ],
  "references": [
    {
      "type": "cve",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-45105",
      "label": "NVD record"
    },
    {
      "type": "vendor_advisory",
      "url": "http://www.openwall.com/lists/oss-security/2021/12/19/1"
    },
    {
      "type": "vendor_advisory",
      "url": "https://logging.apache.org/log4j/2.x/security.html"
    },
    {
      "type": "vendor_advisory",
      "url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
    },
    {
      "type": "vendor_advisory",
      "url": "https://www.oracle.com/security-alerts/cpujan2022.html"
    }
  ],
  "published_at": "2021-12-18T12:15:07.433Z",
  "issued_at": "2026-08-07T16:48:34.775Z",
  "tags": [
    "log4j",
    "java",
    "denial-of-service"
  ]
}