Windows NTFS: Heap-based buffer overflow leads to local privilege escalation
Summary
A heap-based buffer overflow in the Windows NTFS file system driver affects several supported and unsupported Windows 10, Windows 11 and Windows Server releases, including Windows 10 1607 and Windows Server 2016. An authorized local user can exploit it to elevate privileges, for example to SYSTEM level. Exploitation requires local access and a valid account, so the flaw is not remotely exploitable.
Affected
- Windows 10 Version 1607 and Windows Server 2016: builds before 10.0.14393.9612
- Windows 10 Version 1809: 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 and 25H2: builds before 10.0.26100.9711 and 10.0.26200.9711
- Windows 11 Version 26H1: builds before 10.0.28000.3231
- Windows 11 Version 26H2: builds before 10.0.26300.9711
- Windows Server 2012 and 2012 R2: builds before 6.2.9200.26434 and 6.3.9600.23470 (including Server Core)
Fixed in
- Install the October 2026 security update for the affected version. The fixed build is the first build listed above for each version.
- Windows 10 1607 and Server 2016: fixed build 10.0.14393.9612 (per CVE record; third-party sources list KB5126868, not yet confirmed by MSRC)
Workaround
Unknown.
Exploitation
- No known exploitation in the wild.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- No public proof of concept found.
- EPSS 0.00361 (low predicted exploitation probability).
Our recommendation
- Patch all affected Windows systems with the October 2026 security update, starting with Windows 10 1607 and Server 2016 systems.
- Verify the fixed build and KB number in the MSRC Security Update Guide before rollout.
- Treat Windows 10 1607 and Server 2016 as a lifecycle problem: plan an upgrade and check whether Microsoft still provides updates.
- Where patching or upgrading is not possible, isolate the system and restrict local logons.
- Limit local accounts and review privileged accounts on shared systems, terminal servers and file servers.
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 unlikely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5127648, KB5126651, KB5126655, KB5126657, KB5126646, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-83652 msrc.microsoft.com
- Rapid7 vulnerability record CVE-2026-83652 www.rapid7.com
- NVD record via Vulners CVE-2026-83652 vulners.com
- CNA JSON via Vulners CVELIST:CVE-2026-83652 vulners.com
- OpenCVE record CVE-2026-83652 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 2 Nov 2026, 03:26.
Original description (NVD)
Heap-based buffer overflow 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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