Windows Storage: Local privilege escalation due to race condition
Summary
A race condition (CWE-362, also listed as CWE-416 use-after-free) in the Windows Storage component allows an authorized local attacker to elevate privileges. The attack requires a local foothold with low privileges and is not reachable over the network. An attacker who succeeds can gain high impact on confidentiality, integrity and availability, up to SYSTEM level.
Affected
- Windows 10 Version 1809 and Windows Server 2019 (incl. Server Core): builds before 10.0.17763.9376
- Windows 10 Version 21H2: builds before 10.0.19044.7807
- Windows 10 Version 22H2: builds before 10.0.19045.7807
- Windows 11 Version 23H2: builds before 10.0.22631.7652
- Windows 11 Version 24H2: builds before 10.0.26100.9711
- Windows 11 Version 25H2 and 26H2: builds before 10.0.26200.9711 and 10.0.26300.9711
- Windows 11 Version 26H1: builds before 10.0.28000.3231
- Windows Server 2022: builds before 10.0.20348.5761
- Windows Server 2025 (incl. Server Core): builds before 10.0.26100.33650
- Note: the CPE data lists only Windows 10 1809, but the CNA record covers the listed builds above.
Fixed in
- Windows 10 1809 and Server 2019: 10.0.17763.9376
- Windows 10 21H2: 10.0.19044.7807
- Windows 10 22H2: 10.0.19045.7807
- Windows 11 23H2: 10.0.22631.7652
- Windows 11 24H2: 10.0.26100.9711
- Windows 11 25H2 and 26H2: 10.0.26200.9711 and 10.0.26300.9711
- Windows 11 26H1: 10.0.28000.3231
- Windows Server 2022: 10.0.20348.5761
- Windows Server 2025: 10.0.26100.33650
- Verify build numbers against the MSRC Security Update Guide before deployment.
Workaround
Unknown. No workaround is documented in the CVE record. Limiting local administrator rights and enforcing least privilege reduces the risk.
Exploitation
- Not publicly disclosed and not exploited according to Microsoft.
- Microsoft exploitability assessment: Exploitation Less Likely.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- Not listed in CISA KEV; EPSS 0.00202 (below 1%).
- No public proof of concept found in this research.
Our recommendation
- Install the October 2026 Microsoft security update that contains the fix on all affected systems; confirm the KB article in the MSRC portal first.
- Prioritize shared workstations, terminal servers, file servers and hosts used by contractors or non-admin users.
- Check the exact edition and support status of any Windows 10 1809 system; Home and Pro editions are end-of-life.
- Limit local administrator accounts and enforce least privilege.
- Monitor Windows security event logs for unusual access to storage components.
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-2026-69931 msrc.microsoft.com
- Vulners CVE list mirror (CNA record) vulners.com
- Vulners NVD mirror vulners.com
- OpenCVE CVE-2026-69931 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, 09:31.
Original description (NVD)
Concurrent execution using shared resource with improper synchronization ('race condition') 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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