Vulnerability-Lookup

FKIE_CVE-2026-81963

Vulnerability from fkie_nvd - Published: 2026-09-08 18:21 - Updated: 2026-09-09 05:18

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Summary

Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.

References

	URL	Tags
	secure@microsoft.com	https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81963	Patch, Vendor Advisory
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81963	US Government Resource

Impacted products

Vendor	Product	Version
microsoft	windows_11_23h2	*
microsoft	windows_11_23h2	*
microsoft	windows_11_24h2	*
microsoft	windows_11_24h2	*
microsoft	windows_11_25h2	*
microsoft	windows_11_25h2	*
microsoft	windows_11_26h1	*
microsoft	windows_11_26h1	*
microsoft	windows_server_2025	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "platforms": [
            "ARM64-based Systems"
          ],
          "product": "Windows 11 version 23H2",
          "vendor": "Microsoft",
          "versions": [
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            }
          ]
        },
        {
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Windows 11 Version 23H2",
          "vendor": "Microsoft",
          "versions": [
            {
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              "status": "affected",
              "version": "10.0.22631.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "ARM64-based Systems",
            "x64-based Systems"
          ],
          "product": "Windows 11 Version 24H2",
          "vendor": "Microsoft",
          "versions": [
            {
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              "status": "affected",
              "version": "10.0.26100.0",
              "versionType": "custom"
            }
          ]
        },
        {
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            "ARM64-based Systems",
            "x64-based Systems"
          ],
          "product": "Windows 11 Version 25H2",
          "vendor": "Microsoft",
          "versions": [
            {
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              "status": "affected",
              "version": "10.0.26200.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "ARM64-based Systems",
            "x64-based Systems"
          ],
          "product": "Windows 11 version 26H1",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "10.0.28000.2954",
              "status": "affected",
              "version": "10.0.28000.0",
              "versionType": "custom"
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          ]
        },
        {
          "platforms": [
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          "product": "Windows Server 2025",
          "vendor": "Microsoft",
          "versions": [
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              "version": "10.0.26100.0",
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          ]
        }
      ],
      "source": "secure@microsoft.com"
    }
  ],
  "cisaActionDue": "2026-09-22",
  "cisaExploitAdd": "2026-09-08",
  "cisaRequiredAction": "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA\u2019s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA\u2019s \u201cForensics Triage Requirements\u201d (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset\u0027s internet exposure and ensuring adherence to BOD 26-04 patching guidelines.",
  "cisaVulnerabilityName": "Microsoft Windows Link Following Vulnerability",
  "configurations": [
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              "versionEndExcluding": "10.0.22631.7582",
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              "versionEndExcluding": "10.0.22631.7582",
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              "versionEndExcluding": "10.0.26100.9445",
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              "versionEndExcluding": "10.0.26200.9445",
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              "versionEndExcluding": "10.0.28000.2954",
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          "negate": false,
          "operator": "OR"
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  ],
  "cveTags": [],
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    {
      "lang": "en",
      "value": "Improper link resolution before file access (\u0027link following\u0027) in Windows Update Stack allows an authorized attacker to elevate privileges locally."
    }
  ],
  "id": "CVE-2026-81963",
  "lastModified": "2026-09-09T05:18:17.173",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "secure@microsoft.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
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        "ssvcData": {
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          "options": [
            {
              "exploitation": "active"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-07T00:00:00+00:00",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-08T18:21:00.090",
  "references": [
    {
      "source": "secure@microsoft.com",
      "tags": [
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        "Vendor Advisory"
      ],
      "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81963"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "US Government Resource"
      ],
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81963"
    }
  ],
  "sourceIdentifier": "secure@microsoft.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "description": [
        {
          "lang": "en",
          "value": "CWE-59"
        },
        {
          "lang": "en",
          "value": "CWE-284"
        }
      ],
      "source": "secure@microsoft.com",
      "type": "Secondary"
    }
  ]
}

CVE-2026-81963 (GCVE-0-2026-81963)

Vulnerability from cvelistv5 – Published: 2026-09-08 17:19 – Updated: 2026-10-01 23:00

Title

Windows Update Stack Elevation of Privilege Vulnerability

Summary

Improper link resolution before file access ('link following') in Windows Update Stack 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:F/RL:O/RC:C

SSVC

Exploitation: active Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-07 00:00 UTC

CWE

CWE-59 - Improper Link Resolution Before File Access ('Link Following')
CWE-284 - Improper Access Control

Assigner

microsoft mitre root Scorecard

References

2 references

URL	Tags
https://msrc.microsoft.com/update-guide/vulnerabi…	vendor-advisorypatch
https://www.cisa.gov/known-exploited-vulnerabilit…	government-resource

Impacted products

7 products

Vendor	Product	Version
Microsoft	Windows 11 version 23H2	Affected: 10.0.22631.0 , < 10.0.22631.7582 (custom)
Microsoft	Windows 11 Version 23H2	Affected: 10.0.22631.0 , < 10.0.22631.7582 (custom)
Microsoft	Windows 11 Version 24H2	Affected: 10.0.26100.0 , < 10.0.26100.9445 (custom)
Microsoft	Windows 11 Version 25H2	Affected: 10.0.26200.0 , < 10.0.26200.9445 (custom)
Microsoft	Windows 11 version 26H1	Affected: 10.0.28000.0 , < 10.0.28000.2954 (custom)
Microsoft	Windows Server 2025	Affected: 10.0.26100.0 , < 10.0.26100.33438 (custom)
Microsoft	Windows Server 2025 (Server Core installation)	Affected: 10.0.26100.0 , < 10.0.26100.33438 (custom)

Date Public

2026-09-08 14:00

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-81963",
                "options": [
                  {
                    "Exploitation": "active"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-07T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          },
          {
            "other": {
              "content": {
                "dateAdded": "2026-09-08",
                "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81963"
              },
              "type": "kev"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-09T04:25:46.635Z",
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          "shortName": "CISA-ADP"
        },
        "references": [
          {
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            ],
            "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81963"
          }
        ],
        "timeline": [
          {
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            "time": "2026-09-08T00:00:00.000Z",
            "value": "CVE-2026-81963 added to CISA KEV"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
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            "ARM64-based Systems"
          ],
          "product": "Windows 11 version 23H2",
          "vendor": "Microsoft",
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        }
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      "title": "Windows Update Stack Elevation of Privilege Vulnerability"
    }
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    "datePublished": "2026-09-08T17:19:13.121Z",
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    "dateUpdated": "2026-10-01T23:00:57.600Z",
    "state": "PUBLISHED"
  },
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}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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FKIE_CVE-2026-81963

CVE-2026-81963 (GCVE-0-2026-81963)

Tags

Sightings

Nomenclature

Related by attack behaviour