CVE-2026-81963
Microsoft Windows Link Following Vulnerability
Exploited in the wild
This vulnerability is on the CISA Known Exploited Vulnerabilities list, added 2026-09-08. Federal due date: 2026-09-22.
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.
Impact
Microsoft Windows Update Stack contains a link following vulnerability that allows a local attacker to escalate privileges locally up to SYSTEM.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Microsoft | Windows 11 Version 24H2 | from 10.0.26100.0 before 10.0.26100.9445 |
| Microsoft | Windows 11 Version 23H2 | from 10.0.22631.0 before 10.0.22631.7582 |
| Microsoft | Windows Server 2025 | from 10.0.26100.0 before 10.0.26100.33438 |
| Microsoft | Windows 11 Version 26H1 | from 10.0.28000.0 before 10.0.28000.2954 |
| Microsoft | Windows Server 2025 (Server Core Installation) | from 10.0.26100.0 before 10.0.26100.33438 |
| Microsoft | Windows 11 Version 25H2 | from 10.0.26200.0 before 10.0.26200.9445 |
| Microsoft | Windows 11 23h2 | before 10.0.22631.7582 |
| Microsoft | Windows 11 24h2 | before 10.0.26100.9445 |
| Microsoft | Windows 11 25h2 | before 10.0.26200.9445 |
| Microsoft | Windows 11 26h1 | before 10.0.28000.2954 |
| Microsoft | Windows Server 2025 | before 10.0.26100.33438 |