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

Source: https://junglewise.ai/threats/cve-2026-83931-heap-based-buffer-overflow-in-windows-hyper-v-allows-an  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-26  
License: CC BY 4.0 with a link back

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](https://junglewise.ai/threats/technologies/windows-hyper-v), [Microsoft Windows 11 23h2](https://junglewise.ai/threats/technologies/windows-11-23h2), [Microsoft Windows 11 24h2](https://junglewise.ai/threats/technologies/windows-11-24h2), [Microsoft Windows 11 25h2](https://junglewise.ai/threats/technologies/windows-11-25h2), [Microsoft Windows 11 26h1](https://junglewise.ai/threats/technologies/windows-11-26h1), [Microsoft Windows 11 26h2](https://junglewise.ai/threats/technologies/windows-11-26h2), [Microsoft Windows Server 2022](https://junglewise.ai/threats/technologies/windows-server-2022), [Microsoft Windows Server 2025](https://junglewise.ai/threats/technologies/windows-server-2025). Vendors: [Microsoft](https://junglewise.ai/threats/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

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83931](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83931)

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- [Windows Hyper-V access control spoofing vulnerability](https://junglewise.ai/threats/cve-2026-119959-improper-access-control-in-windows-hyper-v-allows-an-authorized)
- [Windows Hyper-V use-after-free privilege elevation](https://junglewise.ai/threats/cve-2026-119826-use-after-free-in-windows-hyper-v-allows-an-authorized-attacker)