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 ↗

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

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

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