Microsoft Windows: Elevation of privilege in Kernel Streaming Service Driver
Summary
A heap-based buffer overflow in the Windows Kernel Streaming Service Driver allows an authorized, locally logged-in attacker to elevate privileges. The attacker needs a low-privileged account and local access, and no user interaction is required. Microsoft rates the flaw Important, and at the time of retrieval Microsoft reported no exploitation.
Affected
- Windows 10 Version 1607 (10.0.14393.0 to before 10.0.14393.9612)
- Windows 10 Version 1809 (10.0.17763.0 to before 10.0.17763.9376)
- Windows 10 Version 21H2 (10.0.19044.0 to before 10.0.19044.7807)
- Windows 10 Version 22H2 (10.0.19045.0 to before fixed build unknown)
- Windows 11 Version 23H2 (10.0.22631.0 to before 10.0.22631.7652)
- Windows 11 Version 24H2 (10.0.26100.0 to before 10.0.26100.9711)
- Windows 11 Version 25H2 (10.0.26200.0 to before 10.0.26200.9711)
- Windows 11 Version 26H1 (10.0.28000.0 to before 10.0.28000.3231)
- Windows 11 Version 26H2 (10.0.26300.0 to before 10.0.26300.9711)
- Windows Server 2012 and Server Core (6.2.9200.0 to before 6.2.9200.26434)
- Windows Server 2012 R2 and Server Core (6.3.9600.0 to before 6.3.9600.23470)
- Windows Server 2016 (10.0.14393.0 to before 10.0.14393.9612)
Fixed in
- Windows 10 1607: 10.0.14393.9612
- Windows 10 1809: 10.0.17763.9376
- Windows 10 21H2: 10.0.19044.7807
- Windows 10 22H2: Unknown.
- Windows 11 23H2: 10.0.22631.7652
- Windows 11 24H2: 10.0.26100.9711
- Windows 11 25H2 and 26H2: 10.0.26200.9711 and 10.0.26300.9711
- Windows 11 26H1: 10.0.28000.3231
- Windows Server 2012 / 2012 R2: 6.2.9200.26434 / 6.3.9600.23470
- Windows Server 2016: 10.0.14393.9612
Workaround
Unknown. No mitigations were documented; patching is the only known fix.
Exploitation
- Microsoft rates exploit code maturity as Unproven and reports no exploitation.
- No public proof of concept was found during research.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- EPSS is 0.00306 (low).
Our recommendation
- Install the October 2026 cumulative update on all affected Windows systems, prioritising multi-user systems, terminal servers and file servers.
- Check for older installations, especially Windows 10 and Server 2012/2016, and confirm whether Server 2012 is still in use.
- Verify the fixed build for Windows 10 22H2 with Microsoft.
- Monitor for unusual privilege escalation on shared systems.
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 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 (vendor advisory) msrc.microsoft.com
- CNA CVE record with fixed builds (Vulners) vulners.com
- Microsoft CVE list (Vulners) vulners.com
- NVD mirror with EPSS (Vulners) vulners.com
- VulDB entry 418253 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, 04:36.
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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