CVE-2026-81963Windows Update Stack Elevation of Privilege Vulnerability
- 7.8HighCVSS base score
- 7.1%Exploitation in 30 daysEPSS · top 5.7% of all CVEs
- YesKnown exploitedin CISA's KEV since 8 Sept 2026
- YesPublic exploitsa reference or SSVC says so
Description
Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Microsoft Windows Link Following Vulnerability.
- Added
- 8 Sept 2026
- Fix due (US federal)
- 22 Sept 2026
- Used by ransomware
- Not known
Apply 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.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 8 Sept 2026.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By microsoft
- 12 days later
· 12 days later
Published
Added to CISA KEV
Known exploited in the wild
- 2 months later
· 2 months later
Record updated
- 1 day later
· 1 day later
EPSS rose above 1%
0.39% → 7.1%
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| microsoftCNA (assigner) | 3.1 | High7.8 | 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 |
| NVDNVD · Analyzed | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 7.1% · top 5.7% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
Microsoft · Windows 11 version 23H2
- affected 10.0.22631.0 – < 10.0.22631.7582
Microsoft · Windows 11 Version 23H2
- affected 10.0.22631.0 – < 10.0.22631.7582
Microsoft · Windows 11 Version 24H2
- affected 10.0.26100.0 – < 10.0.26100.9445
Microsoft · Windows 11 Version 25H2
- affected 10.0.26200.0 – < 10.0.26200.9445
Microsoft · Windows 11 version 26H1
- affected 10.0.28000.0 – < 10.0.28000.2954
Microsoft · Windows Server 2025
- affected 10.0.26100.0 – < 10.0.26100.33438
Microsoft · Windows Server 2025 (Server Core installation)
- affected 10.0.26100.0 – < 10.0.26100.33438
References
References2
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-73889 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-81963)Record last updated .