{
  "crds_version": "0.1",
  "kind": "base",
  "id": "crds:cve-2021-21985",
  "revision": 1,
  "title": "VMware vCenter Server — vSphere Client Plug-in Remote Code Execution",
  "summary": "A plug-in that ships enabled in VMware vCenter Server — the storage health check in the vSphere web client — never validates its input, so anyone who can reach the web port runs commands with unrestricted privileges on the machine hosting vCenter.",
  "source_type": "cve",
  "severity": "critical",
  "cvss": {
    "score": 9.8,
    "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
    "version": "3.1"
  },
  "epss": 0.99999,
  "exploitation": {
    "known_exploited": true,
    "exploit_available": true,
    "attack_complexity": "low",
    "kev_added": "2021-11-03",
    "prerequisites": "Network access to port 443 on the vCenter Server. The affected plug-in is enabled by default. No credentials needed."
  },
  "remediation": {
    "patch_available": true
  },
  "mitre_attack": [
    "T1190"
  ],
  "kill_chain": "initial_access",
  "recommended_action": "Patch vCenter Server per VMware advisory VMSA-2021-0010 and limit who can reach port 443 on it; then check the host for commands run by the web service.",
  "confidence": "high",
  "provenance": [
    {
      "fields": [
        "title",
        "summary",
        "cvss",
        "severity",
        "exploitation.attack_complexity",
        "exploitation.prerequisites",
        "exploitation.exploit_available",
        "references"
      ],
      "source": "https://nvd.nist.gov/vuln/detail/CVE-2021-21985",
      "retrieved_at": "2026-08-07T07:53:55.549Z",
      "confidence": "high",
      "extractor": "claude-code"
    },
    {
      "fields": [
        "exploitation.known_exploited",
        "remediation.patch_available"
      ],
      "source": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "retrieved_at": "2026-08-07T07:53:55.549Z",
      "confidence": "high",
      "extractor": "claude-code"
    },
    {
      "fields": [
        "epss"
      ],
      "source": "https://api.first.org/data/v1/epss?cve=CVE-2021-21985",
      "retrieved_at": "2026-08-07T07:53:55.549Z",
      "confidence": "high",
      "extractor": "claude-code"
    }
  ],
  "references": [
    {
      "type": "cve",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-21985",
      "label": "NVD record"
    },
    {
      "type": "vendor_advisory",
      "url": "https://www.vmware.com/security/advisories/VMSA-2021-0010.html",
      "label": "VMware advisory VMSA-2021-0010"
    },
    {
      "type": "exploit",
      "url": "http://packetstormsecurity.com/files/163487/VMware-vCenter-Server-Virtual-SAN-Health-Check-Remote-Code-Execution.html",
      "label": "Public remote code execution exploit"
    },
    {
      "type": "cisa",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21985",
      "label": "CISA Known Exploited Vulnerabilities entry"
    }
  ],
  "published_at": "2021-05-26T15:15:07.937Z",
  "issued_at": "2026-08-07T07:53:55.549Z",
  "tags": [
    "vmware",
    "vcenter",
    "vsphere",
    "virtualization",
    "input-validation",
    "kev",
    "ransomware"
  ]
}