Windows Hyper-V: Use after free allows local privilege escalation
Summary
A use-after-free flaw in Windows Hyper-V allows a local attacker with low privileges to elevate their privileges. No user interaction is needed, and the impact on confidentiality, integrity and availability is rated high. Only systems with the Hyper-V role or feature enabled are affected, and an attacker first needs a foothold on the host or in a virtual machine.
Affected
- Windows 11 version 23H2: below build 10.0.22631.7711
- Windows 11 version 24H2: below build 10.0.26100.9974
- Windows 11 version 25H2: below build 10.0.26200.9974
- Windows 11 version 26H1: below build 10.0.28000.3501
- Windows 11 version 26H2: below build 10.0.26300.9974
- Windows Server 2022: below build 10.0.20348.5870
- Windows Server 2025 (including Server Core): below build 10.0.26100.33822
- Windows 10 and older Server releases: Unknown.
Fixed in
- Fixed in the November 2026 security update.
- The exact KB number per product could not be confirmed from the vendor advisory; verify it on the MSRC page.
Workaround
- No vendor workaround known.
- Where Hyper-V is not required, removing the Hyper-V role reduces exposure (own recommendation, not a vendor statement).
Exploitation
- Not confirmed in the wild.
- No public proof of concept found.
- CISA SSVC: exploitation none, not automatable, total technical impact.
- The CVE record's temporal vector (E:U) indicates exploit maturity unproven.
Our recommendation
- Prioritise patching Hyper-V hosts in the November 2026 update cycle.
- Confirm the fixed build for each product on the MSRC advisory.
- Review which hosts have Hyper-V enabled and limit local access to them.
- Monitor for unusual privilege escalation activity on Hyper-V hosts.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide: CVE-2026-119826 msrc.microsoft.com
- CVE Record CVE-2026-119826 www.cve.org
- VulDB entry 434169 vuldb.com
- Windows message center (release health) learn.microsoft.com
- Strix.ai CVE-2026-119826 (secondary, unverified) www.strix.ai
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 11 Nov 2026, 03:48.
Original description (NVD)
Use after free in Windows Hyper-V 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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