High severity · published Sep 8, 2026
CVE-2026-81963
Windows Update Stack Elevation of Privilege Vulnerability
In wildKEV
7.8
CVSS
0.4%
EPSS
Yes
On KEV
Description
Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 33% of CVEs
Exploited in the wildYes
CISA KEVListed Sep 8, 2026
Federal remediation dueSep 22, 2026
Ransomware campaign useNot known
Affected products
Which versions
WI
Windows · Microsoft
All versions, or not specified · source: KEV
W1
Windows 11 Version 24H2 · Microsoft
10.0.26100.0 before 10.0.26100.9445 · source: vendor
W1
Windows 11 Version 25H2 · Microsoft
10.0.26200.0 before 10.0.26200.9445 · source: vendor
W1
Windows 11 version 23H2 · Microsoft
10.0.22631.0 before 10.0.22631.7582; 10.0.22631.0 before 10.0.22631.7582 · source: vendor
W1
Windows 11 version 26H1 · Microsoft
10.0.28000.0 before 10.0.28000.2954 · source: vendor
WS
Windows Server 2025 · Microsoft
10.0.26100.0 before 10.0.26100.33438 · source: vendor, NVD
WS
Windows Server 2025 (Server Core installation) · Microsoft
10.0.26100.0 before 10.0.26100.33438 · source: vendor
W1
Windows 11 23h2 · Microsoft
before 10.0.22631.7582; before 10.0.22631.7582 · source: NVD
W1
Windows 11 24h2 · Microsoft
before 10.0.26100.9445; before 10.0.26100.9445 · source: NVD
W1
Windows 11 25h2 · Microsoft
before 10.0.26200.9445; before 10.0.26200.9445 · source: NVD
W1
Windows 11 26h1 · Microsoft
before 10.0.28000.2954; before 10.0.28000.2954 · source: NVD
In the news
AdvisoryHigh
October 2026 Patch Tuesday forecast: Time for an Office cleanup
September 2026 Patch Tuesday set an all-time record with 973 CVEs addressed across the Microsoft portfolio. We’re only four months into the Patch Apocalypse and everyone seems to be numb with respect to the insane number of CVEs reported. Despite this massive number, only two, CVE-2026-85880 and CVE-2026-81963, were reported Known Exploited and none were Publicly Disclosed. So for most of us, it’s still business as usual, patch systems at highest risk, but be prepared … More → The post October 2026 Patch Tuesday forecast: Time for an Office cleanup appeared first on Help Net Security .
Oct 9, 2026·Help Net Security
AdvisoryHigh
CISA Adds Four Known Exploited Vulnerabilities to Catalog
CISA has added four new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog , based on evidence of active exploitation.   CVE-2026-75650 Adobe Commerce and Magento Improper Neutralization of Special Elements Used in a Template Engine Vulnerability CVE-2026-81963 Microsoft Windows Link Following Vulnerability   CVE-2026-85880 Microsoft Windows Heap-Based Buffer Overflow Vulnerability  CVE-2026-86218 N-able N-central Static Code Injection Vulnerability  These types of vulnerabilities are a frequent attack vector for malicious cyber actors and pose significant risks to the federal enterprise. Binding Operational Directive (BOD) 26-04: Prioritizing Security Updates Based on Risk establishes vulnerability management requirements for Federal Civilian Executive Branch (FCEB) agencies. BOD 26-04 reinforces the importance of the KEV Catalog and requires federal agencies to prioritize rapid remediation of high-risk vulnerabilities, specifically those identified by Common Vulnerabilities and Exposures (CVEs) listed in CISA’s KEV Catalog on publicly exposed assets that grant total control of the asset post-exploitation, while deferring action for lower-risk vulnerabilities. BOD 26-04 further establishes basic expectations for when agencies must check whether threat actors compromised the system before the patch was applied. While BOD 26-04 applies only to FCEB agencies, CISA encourages all organizations to adopt risk-based...
Sep 8, 2026·CISA Advisories
VulnerabilityHigh
[CISA KEV] CVE-2026-81963: Microsoft Windows - Microsoft Windows Link Following Vulnerability
Microsoft Windows Update Stack contains a link following vulnerability that allows a local attacker to escalate privileges locally up to SYSTEM.
Sep 8, 2026·CISA KEV
Affected product
WI
Windows
Microsoft
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