Reference page — cumulative record through Saturday, October 3, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-81963

CVE-2026-81963HIGH

Microsoft Windows 11 version 23H2 — Windows Update Stack Elevation of Privilege Vulnerability

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  H  H  H    7.8   .0039   31.2   YES

AFFECTED
  Product                                         Versions        Fixed
  Windows 11 version 23H2                         10.0.22631.0 –  —
  Windows 11 Version 23H2                         10.0.22631.0 –  —
  Windows 11 Version 24H2                         10.0.26100.0 –  —
  Windows 11 Version 25H2                         10.0.26200.0 –  —
  Windows 11 version 26H1                         10.0.28000.0 –  —
  Windows Server 2025                             10.0.26100.0 –  —
  Windows Server 2025 (Server Core installation)  10.0.26100.0 –  —

TIMELINE
  Aug 27  Reserved by microsoft
  Sep 8   ADDED TO KEV — CVE-2026-81963 (Microsoft Windows 11 version 23H2). Remediation due September 22, 2026.
  Sep 8   Published (CNA: microsoft)
  Sep 23  DUE DATE PASSED — CVE-2026-81963 (Microsoft Windows 11 version 23H2). CISA remediation deadline was September 22, 2026; still in catalog.

CWE-59, CWE-284 · CNA: microsoft · CVSS v3.1 · 2 references · NVD status: Analyzed · KEV due September 22, 2026

Description

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

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
August 27, 2026	Reserved	Reserved by microsoft
September 8, 2026	KEV ADDED	ADDED TO KEV — CVE-2026-81963 (Microsoft Windows 11 version 23H2). Remediation due September 22, 2026.
September 8, 2026	Published	Published (CNA: microsoft)
September 23, 2026	DUE DATE PASSED	DUE DATE PASSED — CVE-2026-81963 (Microsoft Windows 11 version 23H2). CISA remediation deadline was September 22, 2026; still in catalog.

Affected

Affected products and packages — 7 rows
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
Microsoft	Windows 11 version 23H2	—	10.0.22631.0	—
Microsoft	Windows 11 Version 23H2	—	10.0.22631.0	—
Microsoft	Windows 11 Version 24H2	—	10.0.26100.0	—
Microsoft	Windows 11 Version 25H2	—	10.0.26200.0	—
Microsoft	Windows 11 version 26H1	—	10.0.28000.0	—
Microsoft	Windows Server 2025	—	10.0.26100.0	—
Microsoft	Windows Server 2025 (Server Core installation)	—	10.0.26100.0	—

Weaknesses

CWE-59 · CWE-284

References (2)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81963 [vendor-advisory, patch]
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81963 [government-resource]

Authoritative record: CVE-2026-81963 at cve.org

Vendors: microsoft

Weaknesses: CWE-59 · CWE-284

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-81963 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Saturday, October 3, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.