Windows Advanced Rasterization Platform: Use-after-free allows local privilege escalation

Summary

A use-after-free flaw in the Windows Advanced Rasterization Platform (WARP), a software renderer component of Windows, allows an authorized local attacker to elevate privileges. The attacker needs a valid low-privilege account on the system, so the flaw is typically a second-stage issue after phishing, malware or stolen credentials. The CVSS score is 8.8 with a scope change, and NVD analysis was still pending at publication.

Affected

• Windows 10 Version 1809 (before 10.0.17763.9376)
• Windows 10 Version 21H2 (before 10.0.19044.7807)
• Windows 10 Version 22H2 (before 10.0.19045.7807)
• Windows 11 Version 23H2 (before 10.0.22631.7652)
• Windows 11 Version 24H2 (before 10.0.26100.9711)
• Windows 11 Version 25H2 (before 10.0.26200.9711)
• Windows 11 Version 26H1 (before 10.0.28000.3231)
• Windows 11 Version 26H2 (before 10.0.26300.9711)
• Windows Server 2019, including Server Core (before 10.0.17763.9376)
• Windows Server 2022 (before 10.0.20348.5761)
• Windows Server 2025, including Server Core (before 10.0.26100.33650)

Fixed in

• Windows 10 1809: 10.0.17763.9376 or later
• Windows 10 21H2: 10.0.19044.7807 or later
• Windows 10 22H2: 10.0.19045.7807 or later
• Windows 11 23H2: 10.0.22631.7652 or later
• Windows 11 24H2: 10.0.26100.9711 or later
• Windows 11 25H2: 10.0.26200.9711 or later
• Windows 11 26H1: 10.0.28000.3231 or later
• Windows 11 26H2: 10.0.26300.9711 or later
• Windows Server 2019: 10.0.17763.9376 or later
• Windows Server 2022: 10.0.20348.5761 or later
• Windows Server 2025: 10.0.26100.33650 or later

The KB number for these builds is unknown. Check the MSRC advisory.

Workaround

Unknown. No vendor workaround has been identified. Install the Windows update.

Exploitation

• Microsoft's temporal metrics mark exploit maturity as Unproven (E:U) and remediation as Official fix (RL:O).
• CISA SSVC lists exploitation as none and automatable as no.
• No public proof of concept or in-the-wild exploitation is known at publication.

Our recommendation

• Install the October 2026 or later Windows cumulative update on all affected systems, as part of the next regular update cycle.
• Prioritise multi-user systems such as terminal servers, file servers and shared workstations.
• Check the MSRC advisory for the exact KB number and confirm the build numbers after patching.
• Monitor for signs of local privilege escalation and review local accounts and their privileges.

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-2026-118217 msrc.microsoft.com
• CVE Record CVE-2026-118217 (CNA: Microsoft) www.cve.org
• Strix CVE-2026-118217 (aggregator mirroring CNA data) www.strix.ai
• Wikipedia: Windows Advanced Rasterization Platform en.wikipedia.org

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 10 Nov 2026, 22:17.