Windows Win32k: Elevation of privilege due to missing authorization

Summary

A flaw in the Win32k kernel component of Windows allows a local, authorized user to elevate privileges. An attacker who already has a foothold on the system, for example through a phished or compromised user account, could gain SYSTEM rights. CVSS 3.1 base score is 7.8 (High) with high impact on confidentiality, integrity and availability.

Affected

• Windows 10 Version 1607 and Windows Server 2016 (including Server Core): 10.0.14393.0 to before 10.0.14393.9688
• Windows 10 Version 1809 and Windows Server 2019 (including Server Core): 10.0.17763.0 to before 10.0.17763.9487
• Windows 10 Version 21H2: 10.0.19044.0 to before 10.0.19044.7846
• Windows 10 Version 22H2: 10.0.19045.0 to before 10.0.19045.7846
• Windows 11 Version 23H2: 10.0.22631.0 to before 10.0.22631.7711
• Windows 11 Version 24H2: 10.0.26100.0 to before 10.0.26100.9974 (build value to be verified on MSRC)
• Windows 11 Version 25H2: 10.0.26200.0 to before 10.0.26200.9974
• Windows 11 Version 26H1: 10.0.28000.0 to before 10.0.28000.3501
• Windows 11 Version 26H2: 10.0.26300.0 to before 10.0.26300.9974
• Windows Server 2022: 10.0.20348.0 to before 10.0.20348.5870

Fixed in

• Install the Microsoft security updates published with the November 2026 Patch Tuesday for the affected version.
• Fixed build numbers are listed in the affected section above; confirm the exact KB number per build in the MSRC Security Update Guide before deployment.

Workaround

• No vendor workaround is known. Unknown.
• Limiting local admin rights and application control reduces the impact but does not fix the flaw.

Exploitation

• No exploitation in the wild found at the time of research.
• No public proof-of-concept found at the time of research.
• CISA SSVC assessment: Exploitation none, Automatable no, Technical Impact total.

Our recommendation

• Patch all affected Windows systems, starting with servers, terminal servers and systems shared by many users.
• Replace or upgrade unsupported Windows 10 builds (1607, 1809, 21H2) or secure them with Extended Security Updates.
• Reduce local admin rights and check which accounts can log on locally to affected systems.
• Monitor endpoints for unusual privilege changes and re-check CISA KEV and public exploit sources.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• Microsoft Security Update Guide: CVE-2026-119899 msrc.microsoft.com
• CVE.org record CVE-2026-119899 www.cve.org
• Strix AI: CVE-2026-119899 (third-party tracker) www.strix.ai
• Senserva: KB5131096 (third-party, unverified) senserva.com

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 03:43.