CVE-2026-83931: Microsoft Windows Hyper-V heap-based buffer overflow

CVE-2026-83931 · Severity: high · CVSS 7.8 · Published 2026-10-13

Windows Hyper-V, Microsoft's virtualization platform, contains a heap-based buffer overflow vulnerability that allows an authorized local attacker to execute arbitrary code on the system. An attacker with legitimate access to a Hyper-V host could exploit this flaw to gain full control of the virtualization infrastructure and potentially access or compromise virtual machines running on it.

Technologies: Microsoft Windows Hyper-V, Microsoft Windows 11 23h2, Microsoft Windows 11 24h2, Microsoft Windows 11 25h2, Microsoft Windows 11 26h1, Microsoft Windows 11 26h2, Microsoft Windows Server 2022, Microsoft Windows Server 2025. Vendors: Microsoft.

Quick answers

Is CVE-2026-83931 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-83931 being exploited in the wild.
How severe is CVE-2026-83931?
High severity, with a CVSS score of 7.8, published 13 October 2026.
Which products and versions are affected?
Microsoft Windows Hyper-V.
Is there a fix for CVE-2026-83931?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-83931 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2026-83931?
Check whether you run Microsoft Windows Hyper-V, Microsoft Windows 11 23h2, Microsoft Windows 11 24h2 or one of the others listed. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A heap-based buffer overflow exists in Windows Hyper-V that can be triggered by an authorized local attacker. The vulnerability requires local access and valid credentials to exploit, allowing arbitrary code execution with the privileges of the Hyper-V process. A patch is available from Microsoft.

Affected products

  • Microsoft Windows Hyper-V

Timeline

  • 2026-10-13: disclosed

References

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