Microsoft Windows Advanced Rasterization Platform: Heap-based buffer overflow leads to local privilege escalation

Summary

A heap-based buffer overflow in the Windows Advanced Rasterization Platform allows an authorized local attacker to elevate privileges. An attacker needs a low-privileged account on the system and no user interaction. The flaw is a post-compromise risk, so it matters most on multi-user systems such as Remote Desktop or terminal servers, shared workstations and VDI.

Affected

• Windows 10 Version 1809 and Windows Server 2019 (including Server Core): builds before 10.0.17763.9376
• Windows 10 Version 21H2: builds before 10.0.19044.7807
• Windows 10 Version 22H2: builds before 10.0.19045.7807
• Windows 11 Version 23H2: builds before 10.0.22631.7652
• Windows 11 Version 24H2 and 25H2, Windows 11 Version 26H2: builds before 10.0.26100.9711 (24H2), 10.0.26200.9711 (25H2) and 10.0.26300.9711 (26H2)
• Windows 11 Version 26H1: builds before 10.0.28000.3231
• Windows Server 2022: builds before 10.0.20348.5761
• Windows Server 2025 (including Server Core): builds before 10.0.26100.33650
• Source: CVE record by Microsoft as CNA; the list of Windows 11 23H2 and Server fixed builds should be verified against MSRC.

Fixed in

Fixed in Microsoft's security updates from November 2026 (Patch Tuesday). Exact KB numbers: Unknown. Verify the fixed build on each system against the MSRC advisory.

Workaround

Unknown.

Exploitation

• Exploitation status according to CISA SSVC: no exploitation known, not automatable, total technical impact.
• No public proof-of-concept exploit found at the time of research.
• Not listed in the CISA KEV catalog as far as could be determined.
• No evidence of in-the-wild exploitation found.

Our recommendation

• Install the November 2026 Windows security update on all affected systems, prioritising multi-user servers, Remote Desktop and terminal servers, shared hosts and VDI.
• Confirm the installed build number on each system against the MSRC advisory.
• Restrict local logon rights and limit untrusted applications on shared systems.
• Monitor for unexpected privilege escalation and re-check the exploitation status, as the CVE was published recently.

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-2026-105020 msrc.microsoft.com
• CVE Record CVE-2026-105020 www.cve.org
• Strix.ai: CVE-2026-105020 www.strix.ai
• Tenable: Microsoft November 2026 Patch Tuesday www.tenable.com
• Zero Day Initiative: November 2026 Security Update Review www.zerodayinitiative.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, 00:10.