Microsoft Windows NTFS: Local elevation of privilege via out-of-bounds read
Summary
A flaw in the NTFS file system component of Windows allows an out-of-bounds read (CWE-125) that can be used for local privilege escalation. An attacker needs a valid local account or code already running as a user; the vulnerability is not reachable over the network. Successful exploitation can impact confidentiality, integrity and availability of the system.
Affected
- Windows 10 Version 1607 (below 10.0.14393.9612)
- Windows 10 Version 1809 (below 10.0.17763.9376)
- Windows 10 Version 21H2 (below 10.0.19044.7807)
- Windows 10 Version 22H2 (below 10.0.19045.7807)
- Windows 11 Version 23H2 (below 10.0.22631.7652)
- Windows 11 Version 24H2 (below 10.0.26100.9711)
- Windows 11 Version 25H2 (below 10.0.26200.9711)
- Windows 11 Version 26H1 (below 10.0.28000.3231)
- Windows 11 Version 26H2 (below 10.0.26300.9711)
- Windows Server 2012 and 2012 Server Core (below 6.2.9200.26434)
- Windows Server 2012 R2 and 2012 R2 Server Core (below 6.3.9600.23470)
- Windows Server 2016 (below 10.0.14393.9612)
Fixed in
- Fixed builds are listed by Microsoft in the security update for CVE-2026-83508 (release date Oct 13, 2026).
- Windows 10 Version 1607: 10.0.14393.9612 according to the CVE record; confirm on the MSRC page before rollout.
- Sources disagree on fixed builds for Windows 11 24H2 and Windows Server 2025 (both in the 26100 branch); verify the exact build on MSRC.
Workaround
Unknown.
Exploitation
- CISA SSVC: exploitation none, automatable no, technical impact total.
- No public proof of concept or in-the-wild exploitation found as of today; this is not proof of absence.
- EPSS score 0.00388 (very low).
Our recommendation
- Identify systems running the affected Windows builds, especially Windows 10 Version 1607 and 1809 and Windows Server 2012 and 2016.
- Apply the Microsoft security update on the next patch cycle, with higher priority for shared or multi-user systems and terminal servers.
- Plan upgrades for unsupported Windows versions, since they will not receive fixes; check the Microsoft lifecycle page for your edition.
- Restrict local logon to necessary users and monitor for a public proof of concept, as local privilege escalation flaws are often chained after an initial compromise.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – 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)
- 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-2026-83508 msrc.microsoft.com
- Vulners: NVD record CVE-2026-83508 vulners.com
- Vulners: CVE list record CVE-2026-83508 vulners.com
- OpenCVE: CVE-2026-83508 app.opencve.io
- Strix: CVE-2026-83508 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, 03:44.
Original description (NVD)
Out-of-bounds read in Windows NTFS 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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