Windows Kernel: Heap-based buffer overflow allows local privilege escalation
Summary
A heap-based buffer overflow in the Windows Kernel of Windows 10 Version 1607 and Windows Server 2016 allows a local attacker to elevate privileges. The attacker needs a valid low-privilege account on the host and must run code locally, but no user interaction is required. The flaw is not remotely exploitable by itself and is most relevant after an initial foothold, for example through phishing or a compromised account.
Affected
- Windows 10 Version 1607 (x86 and x64): builds below 10.0.14393.9612
- Windows Server 2016: builds below 10.0.14393.9612
- The CNA record lists further affected builds for Windows 10 1809, 21H2, 22H2, Windows 11 and Windows Server 2012 and 2012 R2.
Fixed in
- Windows 10 Version 1607 and Windows Server 2016: build 10.0.14393.9612 or later (per CNA record)
- KB number: Unknown. Check the MSRC advisory.
Workaround
Unknown. No vendor workaround found. Interim measures, not from vendor sources: restrict local logon to trusted users and limit who can run code on affected hosts.
Exploitation
- No evidence of exploitation in the wild found.
- OpenCVE lists exploitation as none and automatable as no. CISA SSVC: exploitation none.
- VulDB reports no available exploit.
- No public proof of concept or CISA KEV entry found.
- EPSS 0.00318 (low predicted exploitation probability).
Our recommendation
- Identify all Windows 10 1607 and Windows Server 2016 hosts and confirm their build numbers.
- Install the October 2026 Microsoft security update to reach build 10.0.14393.9612 or later.
- Check whether 1607 is still in mainstream support and plan a migration if it is not.
- Limit local accounts on shared workstations and terminal servers, and monitor for privilege escalation activity.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Kernel
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- 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
- MSRC Security Update Guide: CVE-2026-83833 msrc.microsoft.com
- CVE List record (vulners) vulners.com
- NVD copy (vulners) vulners.com
- OpenCVE: CVE-2026-83833 app.opencve.io
- VulDB: CVE-2026-83833 vuldb.com
- Rapid7 EPSS record (vulners) vulners.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 2 Nov 2026, 02:53.
Original description (NVD)
Heap-based buffer overflow in Windows Kernel 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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