CVE-2026-83646 Active Directory Federation Services (AD FS) Spoofing Vulnerability

{
  "id": "cf33f81f77ee6d1ec7ea47633c084ac54bda965d4eccbe3da1e47c044a5554ad",
  "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83646",
  "method": "llm",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-83646 Active Directory Federation Services (AD FS) Spoofing Vulnerability",
    "summary": "An open redirect in AD FS allows an authorized attacker to perform spoofing over a network.",
    "evidence": "Url redirection to untrusted site ('open redirect') in Active Directory Federation Services (AD FS) allows an authorized attacker to perform spoofing over a network.",
    "products": [
      {
        "name": {
          "value": "Active Directory Federation Services (AD FS)",
          "evidence": "Url redirection to untrusted site ('open redirect') in Active Directory Federation Services (AD FS) allows an authorized attacker to perform spoofing over a network."
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "fixed_cves": [],
    "related_cves": [
      {
        "value": "CVE-2026-83646",
        "evidence": "CVE-2026-83646 Active Directory Federation Services (AD FS) Spoofing Vulnerability"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "official-microsoft-security-updates",
  "document_id": 24937,
  "published_at": "2026-10-13T14:00:00+00:00"
}