Windows NTFS: Improper access control allows local tampering
Summary
A flaw in the Windows NTFS driver (CWE-639, improper access control) allows an authorized local attacker to tamper with data. The CNA rates it CVSS 5.5 (Medium), with high integrity impact and no confidentiality or availability impact. Exploitation requires local access with low privileges and no user interaction, so the risk is mainly on multi-user systems such as file servers and terminal servers.
Affected
- Windows 10 Version 1607 (10.0.14393.0 before 10.0.14393.9688)
- Windows 10 Version 1809 (10.0.17763.0 before 10.0.17763.9487)
- Windows 10 Version 21H2 (10.0.19044.0 before 10.0.19044.7846)
- Windows 10 Version 22H2 (10.0.19045.0 before 10.0.19045.7846)
- Windows 11 Version 23H2 (10.0.22631.0 before 10.0.22631.7711)
- Windows 11 Version 24H2 (10.0.26100.0 before 10.0.26100.9974)
- Windows 11 Version 25H2 (10.0.26200.0 before 10.0.26200.9974)
- Windows 11 Version 26H1 (10.0.28000.0 before 10.0.28000.3501)
- Windows 11 Version 26H2 (10.0.26300.0 before 10.0.26300.9974)
- Windows Server 2016 incl. Server Core (10.0.14393.0 before 10.0.14393.9688)
- Windows Server 2019 incl. Server Core (10.0.17763.0 before 10.0.17763.9487)
- Windows Server 2022 (10.0.20348.0 before 10.0.20348.5870)
Fixed in
- Windows 10 1607 and Windows Server 2016: 10.0.14393.9688 (November 2026 update)
- Windows 10 1809 and Windows Server 2019: 10.0.17763.9487 (November 2026 update)
- Windows 10 21H2: 10.0.19044.7846
- Windows 10 22H2: 10.0.19045.7846
- Windows 11 23H2: 10.0.22631.7711
- Windows 11 24H2: 10.0.26100.9974
- Windows 11 25H2: 10.0.26200.9974
- Windows 11 26H1: 10.0.28000.3501
- Windows 11 26H2: 10.0.26300.9974
- Windows Server 2022: 10.0.20348.5870
- The fix is part of the November 2026 Patch Tuesday updates. Verify exact KB numbers in the MSRC Security Update Guide.
Workaround
Unknown.
Exploitation
- No public proof of concept found.
- No evidence of exploitation in the wild.
- CISA SSVC: exploitation none, not automatable, partial technical impact.
- The CVSS temporal vector reports exploit code maturity as unproven.
Our recommendation
- Install the November 2026 cumulative update on all affected Windows 10, 11 and Server systems, prioritising multi-user file servers and terminal servers.
- Check whether Windows 10 1607, 1809 and 21H2 still receive security updates or require Extended Security Updates.
- Limit local logon and file share permissions to what is needed, and review write access to sensitive shared folders.
- Monitor for unusual file modifications on shared volumes until patching is complete.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Tampering – Windows NTFS
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131291, KB5131085, KB5131096, KB5131090, KB5131087, KB5132061
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide: CVE-2026-113844 msrc.microsoft.com
- CVE Record CVE-2026-113844 www.cve.org
- BleepingComputer: Microsoft November 2026 Patch Tuesday www.bleepingcomputer.com
- Senserva KB 5131085 (third-party) senserva.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, 16:46.
Original description (NVD)
Improper access control in Windows NTFS allows an authorized attacker to perform tampering 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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