Windows Hyper-V: Use after free allows local privilege escalation
Summary
A use-after-free vulnerability (CWE-416) in the Windows Hyper-V virtualization component allows an authorized local attacker to elevate privileges. Successful exploitation would give the attacker higher privileges on the Windows host, which could expose all virtual machines running on it. The attacker needs a local, low-privileged account and no user interaction is required.
Affected
- Windows 11 version 23H2: 10.0.22631.0 before 10.0.22631.7711
- Windows 11 version 24H2: 10.0.26100.0 before 10.0.26100.9974
- Windows 11 version 25H2: 10.0.26200.0 before 10.0.26200.9974 (range from third-party mirror, not confirmed by CNA record)
- Windows 11 version 26H1: 10.0.28000.0 before 10.0.28000.3501 (range from third-party mirror, not confirmed by CNA record)
- Windows 11 version 26H2: 10.0.26300.0 before 10.0.26300.9974 (range from CNA record)
- Windows Server 2022: 10.0.20348.0 before 10.0.20348.5870 (range from CNA record)
- Windows Server 2025 (including Server Core): 10.0.26100.0 before 10.0.26100.33822
- Windows 10 and Server 2016/2019: Unknown.
Fixed in
- November 2026 Patch Tuesday cumulative update for the affected Windows version.
- Fixed builds: see affected versions above; verify against the MSRC Security Update Guide.
Workaround
Unknown. No workaround is documented in the sources reviewed.
Exploitation
- Exploited in the wild: no evidence found. CVSS temporal vector indicates unproven exploit maturity (E:U).
- Public proof of concept: unknown.
- CISA SSVC: Exploitation none, not automatable, total technical impact.
- NVD status: Awaiting Analysis.
Our recommendation
- Install the November 2026 Windows cumulative update on all Hyper-V hosts and on Windows 11 systems with Hyper-V enabled, with priority on Hyper-V hosts.
- Verify the installed build against the MSRC Security Update Guide, as the version ranges come partly from third-party data.
- Limit local logon on Hyper-V hosts and terminal servers to necessary administrators.
- Prioritize multi-user, multi-tenant and RDS hosts; patching in the next regular cycle is acceptable only if no local attacker access is plausible.
- Monitor for unusual local privilege escalation activity on 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-2026-119391 msrc.microsoft.com
- CVE.org CVE Record: CVE-2026-119391 www.cve.org
- Strix: CVE-2026-119391 www.strix.ai
- MSRC: CVE-2026-119947 (sibling Hyper-V advisory) msrc.microsoft.com
- MSRC: CVE-2026-119960 (sibling Hyper-V advisory) msrc.microsoft.com
- Action1: Patch Tuesday November 2026 www.action1.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 11 Nov 2026, 03:54.
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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