Vulnerability · Published Feb 10, 2026 · Assigned by microsoft
CVE-2026-21255Windows Hyper-V Security Feature Bypass Vulnerability
High 8.8
In plain English
A high-severity improper access control in Windows 10 Version 1607 from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities).
Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.4%top 68.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Improper access control in Windows Hyper-V allows an authorized attacker to bypass a security feature locally.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Windows 10 Version 1607 | 10.0.14393.0 – before 10.0.14393.8868 |
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 – before 10.0.17763.8389 |
| Microsoft | Windows 10 Version 21H2 | 10.0.19044.0 – before 10.0.19044.6937 |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 – before 10.0.19045.6937 |
| Microsoft | Windows 11 version 22H3 | 10.0.22631.0 – before 10.0.22631.6649 |
| Microsoft | Windows 11 Version 23H2 | 10.0.22631.0 – before 10.0.22631.6649 |
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 – before 10.0.26100.7840 |
| Microsoft | Windows 11 Version 25H2 | 10.0.26200.0 – before 10.0.26200.7840 |
| Microsoft | Windows 11 version 26H1 | 10.0.28000.0 – before 10.0.28000.1575 |
| Microsoft | Windows 11 Version 26H1 | 10.0.28000.0 – before 10.0.28000.1575 |
| Microsoft | Windows Server 2016 | 10.0.14393.0 – before 10.0.14393.8868 |
| Microsoft | Windows Server 2016 (Server Core installation) | 10.0.14393.0 – before 10.0.14393.8868 |
| Microsoft | Windows Server 2019 | 10.0.17763.0 – before 10.0.17763.8389 |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 – before 10.0.17763.8389 |
| Microsoft | Windows Server 2022 | 10.0.20348.0 – before 10.0.20348.4773 |
| Microsoft | Windows Server 2022, 23H2 Edition (Server Core installation) | 10.0.25398.0 – before 10.0.25398.2149 |
| Microsoft | Windows Server 2025 | 10.0.26100.0 – before 10.0.26100.32370 |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 – before 10.0.26100.32370 |
Weakness: CWE-284 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
References
- Windows Hyper-V Security Feature Bypass Vulnerability vendor-advisory, patch