CVE-2026-77894 Windows Installer Elevation of Privilege Vulnerability

{
  "id": "2c0525a085dfea3dcd72089f85ed5b76f63674922296fcd2989b784aafcef9bb",
  "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-77894",
  "method": "llm",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-77894 Windows Installer Elevation of Privilege Vulnerability",
    "summary": "A race condition in Windows Installer may allow an authorized attacker to elevate privileges locally.",
    "evidence": "Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Installer allows an authorized attacker to elevate privileges locally.",
    "products": [
      {
        "name": {
          "value": "Windows Installer",
          "evidence": "in Windows Installer"
        },
        "prerequisites": [
          {
            "value": "an authorized attacker",
            "evidence": "allows an authorized attacker to elevate privileges locally"
          }
        ],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "fixed_cves": [],
    "related_cves": [
      {
        "value": "CVE-2026-77894",
        "evidence": "CVE-2026-77894 Windows Installer Elevation of Privilege Vulnerability"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "official-microsoft-security-updates",
  "document_id": 26686,
  "published_at": "2026-09-08T14:00:00+00:00"
}