Windows Spaceport.sys: Elevation of privilege through integer overflow
Summary
An authenticated local attacker can exploit an integer overflow or wraparound in the Windows Spaceport.sys kernel driver to elevate privileges. No user interaction is required, and the flaw is not directly reachable from the internet. The risk is mainly for attackers who already have a foothold, such as malware, a compromised standard account or an insider. CVSS 7.8 (High).
Affected
- Windows 11 Version 23H2 (x64 and ARM64): builds below 10.0.22631.7652
- Windows 11 Version 24H2: builds below 10.0.26100.9711
- Windows 11 Version 25H2: builds below 10.0.26200.9711
- Windows 11 Version 26H1: builds below 10.0.28000.3231
- Windows 11 Version 26H2: builds below 10.0.26300.9711
- Windows Server 2022: builds below 10.0.20348.5761
- Windows Server 2025 (including Server Core): builds below 10.0.26100.33650
Fixed in
- Microsoft security update of October 13, 2026 for the affected branches (build numbers as listed above, per CNA and NVD mirrors)
- Verify the exact KB and build on the Microsoft Security Update Guide before rollout; the KB number has not been confirmed for this CVE.
Workaround
Unknown.
Exploitation
- No evidence of exploitation in the wild found at the time of research.
- Microsoft temporal score lists exploit code maturity as Unproven (E:U).
- No public proof of concept found; this does not prove that none exists.
- CISA SSVC: exploitation none, not automatable, total technical impact.
Our recommendation
- Apply the October 2026 cumulative update on all affected Windows 11 and Windows Server systems in the normal patch cycle, prioritising multi-user hosts and file servers.
- Verify the installed build afterwards.
- Make sure the update also covers other Spaceport.sys fixes from 2026.
- Restrict local logon rights and monitor for suspicious privilege escalation.
Information from Microsoft (Patch Tuesday October 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-69934 msrc.microsoft.com
- Vulners: CVE List record CVE-2026-69934 vulners.com
- Vulners: NVD record CVE-2026-69934 vulners.com
- OpenCVE: CVE-2026-69934 app.opencve.io
- Strix: CVE-2026-69934 www.strix.ai
- Microsoft Security Update Guide: CVE-2026-50298 advisory msrc.microsoft.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, 04:44.
Original description (NVD)
Integer overflow or wraparound in Windows Spaceport.sys 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.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.