---
title: "CVE-2026-87705: Windows Hyper-V - Authentication Bypass"
description: "Windows Hyper-V contains a security feature bypass caused by improper verification of the source of a communication channel, letting unauthorized attackers bypass security over an adjacent network, exploit requires network adjacency."
url: https://panop.io/threat-heartbeat/CVE-2026-87705/
---

# CVE-2026-87705 Windows Hyper-V - Authentication Bypass

Windows Hyper-V contains a security feature bypass caused by improper verification of the source of a communication channel, letting unauthorized attackers bypass security over an adjacent network, exploit requires network adjacency.

CVSS base score 7.4 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.35% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-87705)

## Details

Type

Authentication Bypass

Impact

Broken Authentication

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Published

13 October 2026

Updated

15 October 2026

Weakness

[CWE-940](https://cwe.mitre.org/data/definitions/940.html)

## Vendor fix

Update to the latest version of Windows Hyper-V.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-87705](https://nvd.nist.gov/vuln/detail/CVE-2026-87705)
- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-87705](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-87705)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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