Windows 10: Use-after-free in Windows Storage allows local privilege escalation
Summary
A use-after-free vulnerability (CWE-416) with a race condition component (CWE-362) in the Windows Storage component allows an authorized local attacker to elevate privileges. A successful attacker could gain SYSTEM privileges. The attacker needs local code execution or a low-privilege account, and the attack complexity is high. The vulnerability cannot be exploited remotely over the network.
Affected
- Windows 10 Version 1809: 10.0.17763.0 to before 10.0.17763.9376
- Windows Server 2019 (including Server Core): 10.0.17763.0 to before 10.0.17763.9376
- Other listed versions (21H2, 22H2, Windows 11, Server 2022, Server 2025) are also affected according to the CNA record.
Fixed in
- Patch: October 2026 cumulative update KB5126651 (published 13 October 2026) for Windows 10 Version 1809 and Windows Server 2019
- Fixed build per CNA record: 10.0.17763.9376 (not yet verified on the MSRC page)
Workaround
Unknown. No vendor-documented workaround. Apply the patch.
Exploitation
- MSRC: not publicly disclosed, not exploited, exploit code maturity 'Unproven'
- CISA SSVC: exploitation none, automatable no, technical impact total
- OpenCVE lists KEV status as No. A conflicting Tenable signal for another update batch is not confirmed for this CVE. Check the CISA KEV catalog.
Our recommendation
- Include in the October 2026 patch cycle on all Windows 10 1809 and Server 2019 hosts, prioritising multi-user, RDS/terminal and broadly accessible systems
- Verify the fixed build 10.0.17763.9376 on the MSRC page before rollout
- Check the support end date of the specific edition on Microsoft's lifecycle page
- Re-check KEV status with CISA before the change window
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Storage
- 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, KB5126655, KB5126657, KB5126646, KB5127648, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-69856 msrc.microsoft.com
- Vulners CVELIST: CVE-2026-69856 vulners.com
- Tenable: KB5126651 Windows 10 1809 / Server 2019 update www.tenable.com
- OpenCVE: CVE-2026-69856 app.opencve.io
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 4 Nov 2026, 09:33.
Original description (NVD)
Use after free in Windows Storage 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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