CVE-2026-81963
Microsoft Windows 11 version 23H2, Microsoft Windows 11 Version 24H2, Microsoft Windows 11 Version 25H2
Published 8 Sept 2026 · updated 9 Sept 2026 · Analyzed
Exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on 8 Sept 2026, with a remediation deadline of 22 Sept 2026 for US federal agencies.
Required action: 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.
Description
Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81963 · Patch, Vendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81963 · US Government Resource
Covered in The Skim
- You thought patching was bad before? (on The Security Skim)
“Move fast and break things was supposed to be a cautionary tale, not an automated GitHub Action running every forty-five minutes.”