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CISA KEV · ACTIVELY EXPLOITED
HIGH severity

CVE-2026-81963 — Windows 11 23h2

HIGH

CVE-2026-81963 is a high-severity (CVSS 7.8) CWE-59 vulnerability in microsoft windows 11 23h2. It is in CISA's Known Exploited Vulnerabilities catalog (added 2026-09-08) — treat it as actively exploited and patch now. A fix is available — see the affected versions and patch details below.

Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.

Published
Updated
Affected
5 products
Patched
See advisory
Exploits
None indexed
Exploitation data as of Oct 6, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

  • Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2026-09-08. Federal agencies were required to remediate by 2026-09-22.
  • A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2026-81963.

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs31th percentile — riskier than 31% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-81963 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 383,485 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Description

Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.

Affected Products

5 products · 9 configurations
OS
windows 11 23h2microsoft
< 10.0.22631.7582
range
OS
windows 11 24h2microsoft
< 10.0.26100.9445
range
OS
windows 11 25h2microsoft
< 10.0.26200.9445
range
OS
windows 11 26h1microsoft
< 10.0.28000.2954
range
OS
windows server 2025microsoft
< 10.0.26100.33438
range

Detection & mitigation playbook

Vendor / appliance

  1. Detect

    Inventory every microsoft windows 11 23h2 deployment and check each version against the affected-products list above.

  2. Fix

    Apply the microsoft windows 11 23h2 security patch or hotfix for CVE-2026-81963 on the affected version, following the vendor advisory for your exact build.

  3. Workarounds

    Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Frequently Asked Questions

Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.
O3 Security · Runtime Protection

Is CVE-2026-81963 being exploited in your environment?

Detect and block the exploit chain at execution, on systems you cannot patch yet.

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CVE-2026-81963: Windows 11 23h2 (High 7.8, KEV)