{
  "id": "CVE-2026-21510",
  "url": "https://spydr.io/cve/CVE-2026-21510",
  "published": "2026-02-10T18:16:33.170Z",
  "modified": "2026-06-17T10:18:45.110Z",
  "score": 8.8,
  "severity": "high",
  "cvss_version": "3.1",
  "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
  "score_source": "microsoft.com",
  "epss": 0.24226,
  "epss_percentile": 0.97797,
  "exploited": true,
  "kev": {
    "added": "2026-02-10",
    "due": "2026-03-03",
    "action": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.",
    "ransomware": "Unknown",
    "name": "Microsoft Windows Shell Protection Mechanism Failure Vulnerability",
    "notes": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21510 ; https://nvd.nist.gov/vuln/detail/CVE-2026-21510"
  },
  "ssvc_exploitation": "active",
  "vendors": [
    "Microsoft"
  ],
  "products": [
    "Microsoft Windows 10 Version 1607",
    "Microsoft Windows 10 Version 1809",
    "Microsoft Windows 10 Version 21H2",
    "Microsoft Windows 10 Version 22H2",
    "Microsoft Windows 11 version 22H3",
    "Microsoft Windows 11 Version 23H2",
    "Microsoft Windows 11 Version 24H2",
    "Microsoft Windows 11 Version 25H2",
    "Microsoft Windows 11 version 26H1",
    "Microsoft Windows Server 2012",
    "Microsoft Windows Server 2012 (Server Core installation)",
    "Microsoft Windows Server 2012 R2",
    "Microsoft Windows Server 2012 R2 (Server Core installation)",
    "Microsoft Windows Server 2016",
    "Microsoft Windows Server 2016 (Server Core installation)",
    "Microsoft Windows Server 2019",
    "Microsoft Windows Server 2019 (Server Core installation)",
    "Microsoft Windows Server 2022",
    "Microsoft Windows Server 2022, 23H2 Edition (Server Core installation)",
    "Microsoft Windows Server 2025"
  ],
  "cwes": [
    "CWE-693"
  ],
  "description": "Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.",
  "status": "Analyzed",
  "score_type": "Secondary",
  "scores": {
    "cvss_v40": null,
    "cvss_v31": 8.8,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21510",
      "tags": [
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21510",
      "tags": [
        "US Government Resource"
      ]
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2026-21510",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}