Junglewise Threat Intelligence

CVE-2026-20825: Microsoft Windows Hyper-V improper access control information disclosure

CVE-2026-20825 · Severity: medium · CVSS 4.4 · Published 2026-01-13

Technologies: Microsoft Windows 11 24h2, Microsoft Windows Server 2022 23h2, Microsoft Windows Hyper-V, Microsoft Hyper-V, Microsoft Windows 10 22h2, Microsoft Windows 11 23h2, Microsoft Windows 10 1809, Microsoft Windows Server 2025, Microsoft Windows Server 2022, Microsoft Windows 10, Microsoft Windows Server 2019, Microsoft Windows 10 21h2, Microsoft Windows 11 25h2, Microsoft Windows 11. Vendors: Microsoft.

Executive brief

A security vulnerability exists in Microsoft Hyper-V, the virtualization technology used to run multiple operating systems on a single physical server. An authorized user with high-level privileges on the system could exploit this flaw to access sensitive information that should otherwise be restricted. While this could lead to data exposure, the attacker must already have significant access to the local machine to perform the exploit.

Technical details

An information disclosure vulnerability exists in Windows Hyper-V due to improper access control (CWE-284). The flaw allows a local attacker with high privileges (PR:H) to bypass security restrictions and access sensitive data within the virtualization environment. The attack vector is local, meaning the attacker must have direct access to the host or a highly privileged position within the environment. Microsoft has released security updates to address this issue across various versions of Windows 10, Windows 11, and Windows Server. Security engineers should apply the relevant cumulative updates for their specific OS build.

Affected products

  • Microsoft Windows 10 1809, 21H2, 22H2
  • Microsoft Windows 11 22H3, 23H2, 24H2, 25H2
  • Microsoft Windows Server 2019 All versions
  • Microsoft Windows Server 2022 All versions
  • Microsoft Windows Hyper-V All versions

Timeline

  • 2026-01-13: advisory: Initial disclosure by Microsoft and NVD
  • 2026-07-30: other: CVE record modified by Microsoft

References

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