Vulnerability-Lookup

BDU:2026-01806

Vulnerability from fstec - Published: 10.02.2026

Title

Уязвимость механизма CCF (Cluster Client Failover) операционных систем Windows, позволяющая нарушителю повысить свои привилегии

Description

Уязвимость механизма CCF (Cluster Client Failover) операционных систем Windows связана с возможностью использования памяти после освобождения. Эксплуатация уязвимости может позволить нарушителю повысить свои привилегии

Severity ?


                    
                      AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor

Microsoft Corp

Software Name

Windows Server 2016 (Server Core installation), Windows Server 2016, Windows Server 2025, Windows Server 2022, 23H2 Edition (Server Core installation), Windows Server 2025 (Server Core installation), Windows Server 2022 (Server Core installation), Windows Server 2022, Windows Server 2019 (Server Core installation), Windows Server 2019

Software Version

до 10.0.14393.8868 (Windows Server 2016 (Server Core installation)), до 10.0.14393.8868 (Windows Server 2016), до 10.0.26100.32370 (Windows Server 2025), до 10.0.26100.32313 (Windows Server 2025), до 10.0.25398.2149 (Windows Server 2022, 23H2 Edition (Server Core installation)), до 10.0.26100.32370 (Windows Server 2025 (Server Core installation)), до 10.0.26100.32313 (Windows Server 2025 (Server Core installation)), до 10.0.20348.4773 (Windows Server 2022 (Server Core installation)), до 10.0.20348.4711 (Windows Server 2022 (Server Core installation)), до 10.0.20348.4773 (Windows Server 2022), до 10.0.20348.4711 (Windows Server 2022), до 10.0.17763.8389 (Windows Server 2019 (Server Core installation)), до 10.0.17763.8389 (Windows Server 2019)

Possible Mitigations

Использование рекомендаций производителя: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21251

Reference

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21251

CWE

CWE-416

JSON

To clipboard

{
  "CVSS 2.0": "AV:L/AC:L/Au:S/C:C/I:C/A:C",
  "CVSS 3.0": "AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "CVSS 4.0": null,
  "remediation_\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": null,
  "remediation_\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435": null,
  "\u0412\u0435\u043d\u0434\u043e\u0440 \u041f\u041e": "Microsoft Corp",
  "\u0412\u0435\u0440\u0441\u0438\u044f \u041f\u041e": "\u0434\u043e 10.0.14393.8868 (Windows Server 2016 (Server Core installation)), \u0434\u043e 10.0.14393.8868 (Windows Server 2016), \u0434\u043e 10.0.26100.32370 (Windows Server 2025), \u0434\u043e 10.0.26100.32313 (Windows Server 2025), \u0434\u043e 10.0.25398.2149 (Windows Server 2022, 23H2 Edition (Server Core installation)), \u0434\u043e 10.0.26100.32370 (Windows Server 2025 (Server Core installation)), \u0434\u043e 10.0.26100.32313 (Windows Server 2025 (Server Core installation)), \u0434\u043e 10.0.20348.4773 (Windows Server 2022 (Server Core installation)), \u0434\u043e 10.0.20348.4711 (Windows Server 2022 (Server Core installation)), \u0434\u043e 10.0.20348.4773 (Windows Server 2022), \u0434\u043e 10.0.20348.4711 (Windows Server 2022), \u0434\u043e 10.0.17763.8389 (Windows Server 2019 (Server Core installation)), \u0434\u043e 10.0.17763.8389 (Windows Server 2019)",
  "\u0412\u043e\u0437\u043c\u043e\u0436\u043d\u044b\u0435 \u043c\u0435\u0440\u044b \u043f\u043e \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044e": "\u0418\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u044f:\nhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21251",
  "\u0414\u0430\u0442\u0430 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0438\u044f": "10.02.2026",
  "\u0414\u0430\u0442\u0430 \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0433\u043e \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f": "16.02.2026",
  "\u0414\u0430\u0442\u0430 \u043f\u0443\u0431\u043b\u0438\u043a\u0430\u0446\u0438\u0438": "16.02.2026",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": "BDU:2026-01806",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440\u044b \u0434\u0440\u0443\u0433\u0438\u0445 \u0441\u0438\u0441\u0442\u0435\u043c \u043e\u043f\u0438\u0441\u0430\u043d\u0438\u0439 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "CVE-2026-21251",
  "\u0418\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430",
  "\u041a\u043b\u0430\u0441\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043a\u043e\u0434\u0430",
  "\u041d\u0430\u0437\u0432\u0430\u043d\u0438\u0435 \u041f\u041e": "Windows Server 2016 (Server Core installation), Windows Server 2016, Windows Server 2025, Windows Server 2022, 23H2 Edition (Server Core installation), Windows Server 2025 (Server Core installation), Windows Server 2022 (Server Core installation), Windows Server 2022, Windows Server 2019 (Server Core installation), Windows Server 2019",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u041e\u0421 \u0438 \u0442\u0438\u043f \u0430\u043f\u043f\u0430\u0440\u0430\u0442\u043d\u043e\u0439 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u044b": "Microsoft Corp Windows Server 2016 (Server Core installation) \u0434\u043e 10.0.14393.8868 , Microsoft Corp Windows Server 2016 \u0434\u043e 10.0.14393.8868 , Microsoft Corp Windows Server 2025 \u0434\u043e 10.0.26100.32370 , Microsoft Corp Windows Server 2025 \u0434\u043e 10.0.26100.32313 , Microsoft Corp Windows Server 2022, 23H2 Edition (Server Core installation) \u0434\u043e 10.0.25398.2149 , Microsoft Corp Windows Server 2025 (Server Core installation) \u0434\u043e 10.0.26100.32370 , Microsoft Corp Windows Server 2025 (Server Core installation) \u0434\u043e 10.0.26100.32313 , Microsoft Corp Windows Server 2022 (Server Core installation) \u0434\u043e 10.0.20348.4773 , Microsoft Corp Windows Server 2022 (Server Core installation) \u0434\u043e 10.0.20348.4711 , Microsoft Corp Windows Server 2022 \u0434\u043e 10.0.20348.4773 , Microsoft Corp Windows Server 2022 \u0434\u043e 10.0.20348.4711 , Microsoft Corp Windows Server 2019 (Server Core installation) \u0434\u043e 10.0.17763.8389 , Microsoft Corp Windows Server 2019 \u0434\u043e 10.0.17763.8389 ",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c\u0430 CCF (Cluster Client Failover) \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c Windows, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u043f\u043e\u0432\u044b\u0441\u0438\u0442\u044c \u0441\u0432\u043e\u0438 \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438",
  "\u041d\u0430\u043b\u0438\u0447\u0438\u0435 \u044d\u043a\u0441\u043f\u043b\u043e\u0439\u0442\u0430": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "\u0418\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u043f\u043e\u0441\u043b\u0435 \u043e\u0441\u0432\u043e\u0431\u043e\u0436\u0434\u0435\u043d\u0438\u044f (CWE-416)",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c\u0430 CCF (Cluster Client Failover) \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c Windows \u0441\u0432\u044f\u0437\u0430\u043d\u0430 \u0441 \u0432\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u044c\u044e \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u044f \u043f\u0430\u043c\u044f\u0442\u0438 \u043f\u043e\u0441\u043b\u0435 \u043e\u0441\u0432\u043e\u0431\u043e\u0436\u0434\u0435\u043d\u0438\u044f. \u042d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043c\u043e\u0436\u0435\u0442 \u043f\u043e\u0437\u0432\u043e\u043b\u0438\u0442\u044c \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u043f\u043e\u0432\u044b\u0441\u0438\u0442\u044c \u0441\u0432\u043e\u0438 \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438",
  "\u041f\u043e\u0441\u043b\u0435\u0434\u0441\u0442\u0432\u0438\u044f \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": null,
  "\u041f\u0440\u043e\u0447\u0430\u044f \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f": null,
  "\u0421\u0432\u044f\u0437\u044c \u0441 \u0438\u043d\u0446\u0438\u0434\u0435\u043d\u0442\u0430\u043c\u0438 \u0418\u0411": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u0430",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044f": "\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0435 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438": "\u041c\u0430\u043d\u0438\u043f\u0443\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 \u0441\u0442\u0440\u0443\u043a\u0442\u0443\u0440\u0430\u043c\u0438 \u0434\u0430\u043d\u043d\u044b\u0445",
  "\u0421\u0441\u044b\u043b\u043a\u0438 \u043d\u0430 \u0438\u0441\u0442\u043e\u0447\u043d\u0438\u043a\u0438": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21251",
  "\u0421\u0442\u0430\u0442\u0443\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041f\u043e\u0434\u0442\u0432\u0435\u0440\u0436\u0434\u0435\u043d\u0430 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u0435\u043c",
  "\u0422\u0438\u043f \u041f\u041e": "\u041e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u0430\u044f \u0441\u0438\u0441\u0442\u0435\u043c\u0430",
  "\u0422\u0438\u043f \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "CWE-416",
  "\u0423\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0421\u0440\u0435\u0434\u043d\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 2.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 6,8)\n\u0412\u044b\u0441\u043e\u043a\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 3.1 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 7,8)"
}

CVE-2026-21251 (GCVE-0-2026-21251)

Vulnerability from cvelistv5 – Published: 2026-02-10 17:51 – Updated: 2026-02-23 16:23

Title

Cluster Client Failover (CCF) Elevation of Privilege Vulnerability

Summary

Use after free in Windows Cluster Client Failover allows an authorized attacker to elevate privileges locally.

Severity ?

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

CWE

CWE-416 - Use After Free

Assigner

microsoft

References

URL

Tags

https://msrc.microsoft.com/update-guide/vulnerabi…

vendor-advisorypatch

Impacted products

Vendor

Product

Version

Microsoft

Windows Server 2016

Affected: 10.0.14393.0 , < 10.0.14393.8868 (custom)

Microsoft	Windows Server 2016 (Server Core installation)	Affected: 10.0.14393.0 , < 10.0.14393.8868 (custom)
Microsoft	Windows Server 2019	Affected: 10.0.17763.0 , < 10.0.17763.8389 (custom)
Microsoft	Windows Server 2019 (Server Core installation)	Affected: 10.0.17763.0 , < 10.0.17763.8389 (custom)
Microsoft	Windows Server 2022	Affected: 10.0.20348.0 , < 10.0.20348.4773 (custom)
Microsoft	Windows Server 2022, 23H2 Edition (Server Core installation)	Affected: 10.0.25398.0 , < 10.0.25398.2149 (custom)
Microsoft	Windows Server 2025	Affected: 10.0.26100.0 , < 10.0.26100.32370 (custom)
Microsoft	Windows Server 2025 (Server Core installation)	Affected: 10.0.26100.0 , < 10.0.26100.32370 (custom)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-21251",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-06T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-02-11T04:56:05.654Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Windows Server 2016",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "10.0.14393.8868",
              "status": "affected",
              "version": "10.0.14393.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Windows Server 2016 (Server Core installation)",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "10.0.14393.8868",
              "status": "affected",
              "version": "10.0.14393.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Windows Server 2019",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "10.0.17763.8389",
              "status": "affected",
              "version": "10.0.17763.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Windows Server 2019 (Server Core installation)",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "10.0.17763.8389",
              "status": "affected",
              "version": "10.0.17763.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Windows Server 2022",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "10.0.20348.4773",
              "status": "affected",
              "version": "10.0.20348.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Windows Server 2022, 23H2 Edition (Server Core installation)",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "10.0.25398.2149",
              "status": "affected",
              "version": "10.0.25398.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Windows Server 2025",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "10.0.26100.32370",
              "status": "affected",
              "version": "10.0.26100.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Windows Server 2025 (Server Core installation)",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "10.0.26100.32370",
              "status": "affected",
              "version": "10.0.26100.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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              "negate": false,
              "operator": "OR"
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          ]
        }
      ],
      "datePublic": "2026-02-10T16:00:00.000Z",
      "descriptions": [
        {
          "lang": "en-US",
          "value": "Use after free in Windows Cluster Client Failover allows an authorized attacker to elevate privileges locally."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C",
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            }
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      ],
      "problemTypes": [
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              "description": "CWE-416: Use After Free",
              "lang": "en-US",
              "type": "CWE"
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          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-23T16:23:18.194Z",
        "orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
        "shortName": "microsoft"
      },
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          "name": "Cluster Client Failover (CCF) Elevation of Privilege Vulnerability",
          "tags": [
            "vendor-advisory",
            "patch"
          ],
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21251"
        }
      ],
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    "dateReserved": "2025-12-11T21:02:05.736Z",
    "dateUpdated": "2026-02-23T16:23:18.194Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

BDU:2026-01806

CVE-2026-21251 (GCVE-0-2026-21251)

Tags

Sightings

Nomenclature