Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-27918

CVE-2026-27918HIGH

Microsoft Windows 10 Version 1809 — Windows Shell Elevation of Privilege Vulnerability

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   H   L   N  U  H  H  H    7.0   .0019    8.2     —

AFFECTED
  Product                                         Versions        Fixed
  Windows 10 Version 1809                         10.0.17763.0 –  —
  Windows 10 Version 21H2                         10.0.19044.0 –  —
  Windows 10 Version 22H2                         10.0.19045.0 –  —
  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 2019                             10.0.17763.0 –  —
  Windows Server 2019 (Server Core installation)  10.0.17763.0 –  —
  + 4 more

TIMELINE
  Feb 24  Reserved by microsoft
  Apr 14  Published (CNA: microsoft)
  Oct 14  RESCORED — CVE-2026-27918 (Microsoft Windows 10 Version 1809). CVSS 7.8 → 7 (NVD).

CWE-362 · CNA: microsoft · CVSS v3.1 · 1 reference · NVD status: Analyzed

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Shell allows an authorized attacker to elevate privileges locally.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
February 24, 2026	Reserved	Reserved by microsoft
April 14, 2026	Published	Published (CNA: microsoft)
October 14, 2026	RESCORED	RESCORED — CVE-2026-27918 (Microsoft Windows 10 Version 1809). CVSS 7.8 → 7 (NVD).

Affected

Affected products and packages — 14 rows
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
Microsoft	Windows 10 Version 1809	—	10.0.17763.0	—
Microsoft	Windows 10 Version 21H2	—	10.0.19044.0	—
Microsoft	Windows 10 Version 22H2	—	10.0.19045.0	—
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 2019	—	10.0.17763.0	—
Microsoft	Windows Server 2019 (Server Core installation)	—	10.0.17763.0	—
Microsoft	Windows Server 2022	—	10.0.20348.0	—
Microsoft	Windows Server 2022, 23H2 Edition (Server Core installation)	—	10.0.25398.0	—
Microsoft	Windows Server 2025	—	10.0.26100.0	—
Microsoft	Windows Server 2025 (Server Core installation)	—	10.0.26100.0	—

Weaknesses

CWE-362

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-27918 [vendor-advisory, patch]

Authoritative record: CVE-2026-27918 at cve.org

Vendors: microsoft

Weaknesses: CWE-362

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-27918 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 Monday, October 19, 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.