Microsoft Windows: Use-after-free in Winlogon allows local privilege escalation
Summary
A use-after-free vulnerability (CWE-416) in the Windows Winlogon component allows an authorized local user to elevate privileges. The attack requires local access with low privileges and high complexity, and it is not reachable from the network. A successful attacker can gain SYSTEM-level control, so shared hosts and multi-user systems are at greatest risk.
Affected
- Windows 10 Version 1809 (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)
- 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 2019 and Server Core installation (10.0.17763.0 to before 10.0.17763.9487)
- Windows Server 2022 (10.0.20348.0 to before 10.0.20348.5870)
- Windows Server 2025 and Server Core installation (10.0.26100.0 to before 10.0.26100.33822)
Fixed in
- Install the Microsoft security update released on November 10, 2026 for your Windows version.
- Fixed builds per the CVE record: 10.0.17763.9487 (1809, Server 2019), 10.0.19044.7846 (21H2), 10.0.19045.7846 (22H2), 10.0.22631.7711 (23H2), 10.0.26100.9974 (24H2), 10.0.26200.9974 (25H2), 10.0.28000.3501 (26H1), 10.0.26300.9974 (26H2), 10.0.20348.5870 (Server 2022), 10.0.26100.33822 (Server 2025).
- KB number: Unknown.
Workaround
- Unknown. No vendor workaround was identified; apply the update.
Exploitation
- Microsoft lists the vulnerability as not exploited and not publicly disclosed.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- No public proof of concept was found in research at the time of writing.
Our recommendation
- Install the November 2026 Windows security update on all affected workstations and servers, prioritizing terminal servers, RDS hosts and multi-user PCs.
- Verify the installed build with winver or the update history, and check the MSRC page for the exact fixed build of your version.
- Check Microsoft lifecycle pages for older builds (1809, 21H2, 22H2) and plan upgrades or ESU enrollment.
- Limit interactive logon to shared hosts and remove unnecessary local administrator rights to reduce the impact of a local escalation.
- Monitor for unusual privilege changes and new SYSTEM processes on endpoints.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Winlogon
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131085, KB5131096, KB5131090, KB5131087, KB5132061, KB5132043
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide: CVE-2026-105522 msrc.microsoft.com
- CVE.org Record: CVE-2026-105522 www.cve.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 11 Nov 2026, 09:43.
Original description (NVD)
Use after free in Winlogon allows an authorized attacker to elevate privileges locally.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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