Windows: Use-after-free in kernel allows local privilege escalation
Summary
A use-after-free flaw (CWE-416) in the Windows kernel allows an authorized local attacker to elevate privileges. The attacker needs a local session with low privileges, and no user interaction is required. Successful exploitation would give full control over the affected system, so a local foothold could become SYSTEM access.
Affected
- Windows 10 Version 1809 (including Windows 10 LTSC 2019): builds 10.0.17763.0 to before 10.0.17763.9376
- Windows Server 2019 (including Server Core): builds 10.0.17763.0 to before 10.0.17763.9376
- Windows 10 Version 21H2: builds 10.0.19044.0 to before 10.0.19044.7807
- Windows 10 Version 22H2: builds 10.0.19045.0 to before 10.0.19045.7807 (the CNA record value appears to be an error, verify on MSRC)
- Windows 11 Versions 23H2, 24H2, 25H2, 26H1 and 26H2 (see CNA record for build ranges)
- Windows Server 2022: builds 10.0.20348.0 to before 10.0.20348.5761
- Windows Server 2025 (including Server Core): builds 10.0.26100.0 to before 10.0.26100.33650
Fixed in
- Fixed in the Microsoft security update of October 13, 2026 (October 2026 cumulative update) for the affected Windows versions
- Fixed builds according to the CNA record: Windows 10 1809 and Server 2019 10.0.17763.9376; Windows 10 21H2 10.0.19044.7807; Windows 11 23H2 10.0.22631.7652; Windows 11 24H2 and Server 2025 10.0.26100.9711 and 10.0.26100.33650; Windows Server 2022 10.0.20348.5761
- Exact KB numbers: Unknown. Take them from the MSRC advisory.
Workaround
Unknown. No vendor workaround is documented. Patching is the only documented remedy.
- General hardening reduces exposure but is not a fix: least privilege, restricted interactive and remote desktop logon, and endpoint detection and response (EDR).
Exploitation
- Not listed in the CISA Known Exploited Vulnerabilities catalog.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- Microsoft exploit code maturity: Unproven.
- Public proof-of-concept code: Unknown. A possible link to a public entry has not been verified.
Our recommendation
- Install the October 2026 cumulative update on all affected Windows 10, Windows 11 and Windows Server systems. Use Windows Update, WSUS or Intune.
- Prioritize systems with shared users, remote desktop or terminal access, and servers where local accounts pose a risk.
- Check whether any Windows 10 1809 or Server 2019 systems are still in use and whether they still receive extended support.
- Verify the fixed build numbers on the MSRC advisory before rollout. Re-check the NVD status, because sources differ.
- Monitor for unusual local privilege escalation and restrict local logon rights.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Kernel
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5126651, KB5126657, KB5126655, KB5126653, KB5127648, KB5126646
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-96317 msrc.microsoft.com
- Theori bug tracker: CVE-2026-96317 github.com
- Vulners CVE record: CVE-2026-96317 vulners.com
- OpenCVE: CVE-2026-96317 app.opencve.io
- Strix CVE summary: CVE-2026-96317 www.strix.ai
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 2 Nov 2026, 00:52.
Original description (NVD)
Use after free in Windows Kernel 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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