Microsoft Windows LSASS: Use-after-free leads to local privilege escalation

Summary

A use-after-free flaw (CWE-416) in the Windows Local Security Authority Subsystem Service (LSASS) allows an authorized local attacker to elevate privileges. Exploitation requires local access with low privileges and no user interaction. A successful attack could give the attacker SYSTEM rights and high impact on confidentiality, integrity and availability.

Affected

• Windows 10 Version 1607, 1809, 21H2 and 22H2
• Windows 11 Version 23H2, 24H2, 25H2, 26H1 and 26H2
• Windows Server 2016 (including Server Core), 2019 (including Server Core) and 2022
• Exact affected ranges: see the CVE record and the MSRC advisory

Fixed in

• Windows 10 1607: 10.0.14393.9688 or later
• Windows 10 1809: 10.0.17763.9487 or later
• Windows 10 21H2: 10.0.19044.7846 or later
• Windows 10 22H2: 10.0.19045.7846 or later
• Windows 11 23H2: 10.0.22631.7711 or later
• Windows 11 24H2: 10.0.26100.9974 or later
• Windows 11 25H2: 10.0.26200.9974 or later
• Windows 11 26H1: 10.0.28000.3501 or later
• Windows 11 26H2: 10.0.26300.9974 or later
• Windows Server 2016: 10.0.14393.9688 or later
• Windows Server 2019: 10.0.17763.9487 or later
• Windows Server 2022: 10.0.20348.5870 or later
• Verify the fixed builds in the MSRC advisory

Workaround

No workaround documented. Unknown whether Microsoft has published an interim mitigation for this CVE.

Exploitation

• No known exploitation in the wild.
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• No public proof-of-concept exploit found in the indexes checked. Absence from these indexes does not prove that no exploit exists.

Our recommendation

• Install the November 2026 security update on all affected Windows systems, prioritising servers, terminal servers and shared workstations.
• Check the installed build with winver or ver and compare it with the fixed build for your edition.
• Identify Windows 10 1607 and 1809 systems and check whether they still receive updates.
• Limit local logon rights and monitor for signs of privilege escalation.
• Recheck NVD and CISA KEV for status changes.

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-2026-85801 msrc.microsoft.com
• CVE Record CVE-2026-85801 www.cve.org
• Strix CVE details: CVE-2026-85801 www.strix.ai
• OffSeq Radar: CVE-2026-85801 radar.offseq.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, 03:22.