Windows 10 1607: Heap-based buffer overflow in WMI allows privilege escalation
Summary
Windows 10 Version 1607 contains a heap-based buffer overflow in Windows Management Instrumentation (WMI). An authorized local user with low privileges can exploit it to elevate privileges, with high impact on confidentiality, integrity and availability. The attacker needs a local logon and no user interaction, and the flaw is not exploitable remotely. Microsoft has released a fix, and no public exploit or active exploitation is known.
Affected
- Microsoft Windows 10 Version 1607: builds 10.0.14393.0 up to, but not including, 10.0.14393.9612
Fixed in
- Build 10.0.14393.9612 or later (per CNA range; verify on the MSRC page)
- KB number: unknown
Workaround
Unknown.
Exploitation
- No exploitation in the wild known.
- CISA SSVC: Exploitation none, not automatable, total technical impact.
- No public proof of concept found.
- EPSS about 0.3%.
Our recommendation
- Install the Microsoft security update for Windows 10 1607 (build 10.0.14393.9612 or later) as a priority on shared PCs, terminal hosts and workstations with local accounts.
- Check that the system still receives Microsoft security updates. Unsupported builds get no fix, so upgrade them.
- Inventory all 1607 systems and verify the installed build.
- Monitor for unusual local privilege escalation activity.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Management Instrumentation
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5126835, KB5126836, KB5126868, KB5126651, KB5126657, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-96856 msrc.microsoft.com
- OpenCVE: CVE-2026-96856 (CNA data and CISA SSVC) app.opencve.io
- Vulners: CVE-2026-96856 vulners.com
- VulDB: CVE-2026-96856 (exploit status, unverified details) vuldb.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, 00:48.
Original description (NVD)
Heap-based buffer overflow in Windows Management Instrumentation 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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