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Description

Improper access control in Windows Hyper-V allows an authorized attacker to bypass a security feature locally.

PUBLISHED Reserved 2025-12-11 | Published 2026-02-10 | Updated 2026-02-23 | Assigner microsoft




HIGH: 8.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C

Problem types

CWE-284: Improper Access Control

Product status

10.0.14393.0 (custom) before 10.0.14393.8868
affected

10.0.17763.0 (custom) before 10.0.17763.8389
affected

10.0.19044.0 (custom) before 10.0.19044.6937
affected

10.0.19045.0 (custom) before 10.0.19045.6937
affected

10.0.22631.0 (custom) before 10.0.22631.6649
affected

10.0.22631.0 (custom) before 10.0.22631.6649
affected

10.0.26100.0 (custom) before 10.0.26100.7840
affected

10.0.26200.0 (custom) before 10.0.26200.7840
affected

10.0.28000.0 (custom) before 10.0.28000.1575
affected

10.0.28000.0 (custom) before 10.0.28000.1575
affected

10.0.14393.0 (custom) before 10.0.14393.8868
affected

10.0.14393.0 (custom) before 10.0.14393.8868
affected

10.0.17763.0 (custom) before 10.0.17763.8389
affected

10.0.17763.0 (custom) before 10.0.17763.8389
affected

10.0.20348.0 (custom) before 10.0.20348.4773
affected

10.0.25398.0 (custom) before 10.0.25398.2149
affected

10.0.26100.0 (custom) before 10.0.26100.32370
affected

10.0.26100.0 (custom) before 10.0.26100.32370
affected

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21255 (Windows Hyper-V Security Feature Bypass Vulnerability) vendor-advisory patch

cve.org (CVE-2026-21255)

nvd.nist.gov (CVE-2026-21255)

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