{"id":"CVE-2026-21255","published":"2026-02-10T17:51:38Z","modified":"2026-08-19T16:26:08Z","title":"Windows Hyper-V Security Feature Bypass Vulnerability","vendor":"Microsoft","product":"Windows 10 Version 1607","tier":"tail","description":{"text":"Improper access control in Windows Hyper-V allows an authorized attacker to bypass a security feature locally.","provenance":"source","from":"CVE.org"},"cvss":{"score":8.8,"severity":"HIGH","version":"3.1","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","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.0038,"percentile":0.31924,"provenance":"source"},"cwes":[{"id":"CWE-284","name":"Improper Access Control"}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21255","tags":["vendor-advisory","patch"]}],"priority":{"score":12.5,"factors":[{"name":"EPSS percentile","points":6.38},{"name":"CVSS severity","points":6.16}]},"vendorSlug":"microsoft","affectedVersions":[{"vendor":"Microsoft","product":"Windows 10 Version 1607","versions":[">= 10.0.14393.0, < 10.0.14393.8868"]},{"vendor":"Microsoft","product":"Windows 10 Version 1809","versions":[">= 10.0.17763.0, < 10.0.17763.8389"]},{"vendor":"Microsoft","product":"Windows 10 Version 21H2","versions":[">= 10.0.19044.0, < 10.0.19044.6937"]},{"vendor":"Microsoft","product":"Windows 10 Version 22H2","versions":[">= 10.0.19045.0, < 10.0.19045.6937"]},{"vendor":"Microsoft","product":"Windows 11 version 22H3","versions":[">= 10.0.22631.0, < 10.0.22631.6649"]},{"vendor":"Microsoft","product":"Windows 11 Version 23H2","versions":[">= 10.0.22631.0, < 10.0.22631.6649"]},{"vendor":"Microsoft","product":"Windows 11 Version 24H2","versions":[">= 10.0.26100.0, < 10.0.26100.7840"]},{"vendor":"Microsoft","product":"Windows 11 Version 25H2","versions":[">= 10.0.26200.0, < 10.0.26200.7840"]},{"vendor":"Microsoft","product":"Windows 11 version 26H1","versions":[">= 10.0.28000.0, < 10.0.28000.1575"]},{"vendor":"Microsoft","product":"Windows 11 Version 26H1","versions":[">= 10.0.28000.0, < 10.0.28000.1575"]}],"euvd":{"id":"EUVD-2026-7328","exploited":false,"provenance":"source"},"lineage":{"familyId":"fam-class-microsoft-windows-cwe-284"}}