CVE-2026-66303 Skype for Business and Lync Denial of Service Vulnerability

{
  "id": "90b98686c8c9e9fd677d71cb10c943fb7632a08f7874cfc758962b5664db97f7",
  "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66303",
  "method": "llm",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-66303 Skype for Business and Lync Denial of Service Vulnerability",
    "summary": "A null pointer dereference in Skype for Business may let an authorized attacker cause a denial of service over a network.",
    "evidence": "Null pointer dereference in Skype for Business allows an authorized attacker to deny service over a network.",
    "products": [
      {
        "name": {
          "value": "Skype for Business",
          "evidence": "CVE-2026-66303 Skype for Business and Lync Denial of Service Vulnerability"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "fixed_cves": [],
    "related_cves": [
      {
        "value": "CVE-2026-66303",
        "evidence": "CVE-2026-66303 Skype for Business and Lync Denial of Service Vulnerability"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "official-microsoft-security-updates",
  "document_id": 27202,
  "published_at": "2026-09-08T14:00:00+00:00"
}