CVE-2026-87699 Winlogon Elevation of Privilege Vulnerability

{
  "id": "037148b4ff41ac9fa501a71d72c0c75fb6c2fd3e4638bb6cc34769e1f121baf6",
  "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-87699",
  "method": "llm",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-87699 Winlogon Elevation of Privilege Vulnerability",
    "summary": "A heap-based buffer overflow in Winlogon could allow an authorized attacker to elevate privileges locally.",
    "evidence": "Heap-based buffer overflow in Winlogon allows an authorized attacker to elevate privileges locally.",
    "products": [
      {
        "name": {
          "value": "Winlogon",
          "evidence": "Heap-based buffer overflow in Winlogon"
        },
        "prerequisites": [
          {
            "value": "authorized attacker",
            "evidence": "allows an authorized attacker to elevate privileges locally"
          }
        ],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "fixed_cves": [],
    "related_cves": [
      {
        "value": "CVE-2026-87699",
        "evidence": "CVE-2026-87699 Winlogon Elevation of Privilege Vulnerability"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "official-microsoft-security-updates",
  "document_id": 25623,
  "published_at": "2026-10-13T14:00:00+00:00"
}