Windows Win32k: Out-of-bounds read allows local privilege escalation

Summary

A out-of-bounds read in the Win32k kernel-mode graphics component of Windows allows an authorized local attacker to elevate privileges. The attacker needs low privileges and local access, so this is a follow-on step after an initial foothold such as a phished user, malware or a compromised low-privilege account. The CVSS base score is 7.8 (High), with high impact on confidentiality, integrity and availability once the attacker is local.

Affected

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

Fixed in

• Install the November 2026 cumulative update for each affected Windows branch, which contains the fixed builds listed above.
• Exact KB numbers per branch: Unknown. Verify them in the MSRC Security Update Guide before rollout.

Workaround

Unknown. No vendor-documented workaround or mitigation is known; patching is the fix.

Exploitation

• No evidence of active exploitation in the sources checked.
• Not listed in CISA KEV in the sources checked.
• No public disclosure or proof of concept found before the patch.
• EPSS score: Unknown.

Our recommendation

• Deploy the November 2026 cumulative update, starting with multi-user systems, terminal and RDS servers and shared PCs.
• Check that Windows 10 systems in scope are patched or replaced, since they are part of the affected list.
• Restrict local logon to necessary users and monitor for unusual privilege changes.
• Re-check NVD, CISA KEV and MSRC for changes, because NVD analysis was still pending at publication.

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

• MSRC Security Update Guide: CVE-2026-105028 msrc.microsoft.com
• CVE Record: CVE-2026-105028 www.cve.org
• Strix AI: CVE-2026-105028 www.strix.ai
• Senserva KB5132059 (November 2026 Windows update) senserva.com
• Senserva KB5131096 (Windows 10 21H2 update) senserva.com
• Trinetriops: November 2026 Patch Tuesday trinetriops.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, 04:38.