CVE-2026-81963Windows Update Stack Elevation of Privilege Vulnerability
Updated under an hour ago ()
Does this affect you?
It affects Microsoft Windows 11 version 23H2 and 4 other products. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Sep 8, 2026; federal agencies had to remediate by Sep 22, 2026. Treat that date as your deadline.
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Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.
- CVSS
- 7.8 HIGH (v3.1, CNA)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
- Weakness (CWE)
- CWE-59, CWE-284
- Known exploited
- Added to CISA KEV Sep 8, 2026; federal remediation due Sep 22, 2026Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (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's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- EPSS (exploitation in the next 30 days)
- 0.39% (percentile 32)
- Assigned by
- microsoft
- NVD analysis
- Analyzed
- Record last updated
- Oct 14, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Microsoft Windows 11 version 23H2 microsoft:windows_11_23h2 | from 10.0.22631.0 before 10.0.22631.7582 | CNA record |
Microsoft Windows 11 Version 24H2 microsoft:windows_11_24h2 | from 10.0.26100.0 before 10.0.26100.9445 | CNA record |
Microsoft Windows 11 Version 25H2 microsoft:windows_11_25h2 | from 10.0.26200.0 before 10.0.26200.9445 | CNA record |
Microsoft Windows 11 version 26H1 microsoft:windows_11_26h1 | from 10.0.28000.0 before 10.0.28000.2954 | CNA record |
Microsoft Windows Server 2025 microsoft:windows_server_2025 (from the name) | from 10.0.26100.0 before 10.0.26100.33438 | CNA record |
microsoft windows_11_23h2 microsoft:windows_11_23h2 | before 10.0.22631.7582; before 10.0.22631.7582 | NVD |
microsoft windows_11_24h2 microsoft:windows_11_24h2 | before 10.0.26100.9445; before 10.0.26100.9445 | NVD |
microsoft windows_11_25h2 microsoft:windows_11_25h2 | before 10.0.26200.9445; before 10.0.26200.9445 | NVD |
microsoft windows_11_26h1 microsoft:windows_11_26h1 | before 10.0.28000.2954; before 10.0.28000.2954 | NVD |
microsoft windows_server_2025 microsoft:windows_server_2025 | before 10.0.26100.33438 | NVD |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81963vendor-advisory, patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.