Windows 10 1607: Heap-based buffer overflow enables local privilege escalation
Summary
Microsoft Windows 10 Version 1607 and Windows Server 2016 contain a heap-based buffer overflow in the Kernel Streaming Service driver, which Microsoft's advisory titles 'Kernel Streaming Service Driver Elevation of Privilege Vulnerability'. An authenticated local user or code already running on the host can exploit it to gain higher privileges, including SYSTEM-level control. The attack vector is local only, so remote exploitation over the network is not possible.
Affected
- Windows 10 Version 1607 (builds before 10.0.14393.9612)
- Windows Server 2016 and Server Core installations (builds before 10.0.14393.9612)
Fixed in
- OS Build 10.0.14393.9612, released 13 Oct 2026 as KB5126868
Workaround
- None known. Microsoft has not published a workaround for this CVE.
- For devices that cannot be patched, restrict local logon to trusted users, enforce application control and isolate the device (own recommendation, not from a vendor source).
Exploitation
- Not exploited in the wild, according to Microsoft.
- Not publicly disclosed, according to Microsoft.
- No public proof of concept found.
- EPSS score 0.00242.
Our recommendation
- Install KB5126868 (build 14393.9612) on all Windows 10 1607 and Server 2016 systems. Test first, as the update has known issues with some on-premises Exchange servers.
- Windows 10 Enterprise LTSB 2016 reached end of updates on 13 Oct 2026, so no further fixes are expected for this build. Plan to replace these devices, or obtain the upgrade path from device suppliers.
- Restrict local accounts and untrusted code on shared or legacy machines, and monitor for unusual privilege changes.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Microsoft Streaming Service
- 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-2026-69970 msrc.microsoft.com
- Microsoft Release Health: Windows 10 1607 and Windows Server 2016 learn.microsoft.com
- Vulners MSRC mirror: MS:CVE-2026-69970 vulners.com
- VulDB: vuln 418275 vuldb.com
- Rapid7 via Vulners: RAPID7:CVE-2026-69970 vulners.com
- Wikipedia: Windows 10, version 1607 en.wikipedia.org
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 4 Nov 2026, 09:27.
Original description (NVD)
Heap-based buffer overflow in Microsoft Streaming Service 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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