Improper Verification of Source of a Communication Channel in Microsoft Windows and Windows Server - CVE-2026-87705

Vulnerability details

The vulnerability allows a remote attacker on the local network to bypass a security feature and disclose sensitive information.

The vulnerability exists due to improper verification of the source of a communication channel in Windows Hyper-V when handling communications over an adjacent network. A remote attacker on the local network can exploit the communication-channel source verification weakness to bypass a security feature and disclose sensitive information.

The relevant virtualization security boundary is between guest virtual machines.

Affected software

How to mitigate CVE-2026-87705

External References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-87705
• https://support.microsoft.com/help/5126651

Related Security Bulletins

• Multiple vulnerabilities in Microsoft Windows