Windows Hyper-V Remote Code Execution Vulnerability

published 2026-02-10 8 mo ago modified 2026-08-19 2 mo ago also EUVD-2026-7351

cvss: 7.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits: 0; none known

Improper input validation in Windows Hyper-V allows an authorized attacker to execute code locally.

Patch / fix

fixed in 17 links 1

Microsoft Windows 10 Version 1607 10.0.14393.8868
Microsoft Windows 10 Version 1809 10.0.17763.8389
Microsoft Windows 10 Version 21H2 10.0.19044.6937
Microsoft Windows 10 Version 22H2 10.0.19045.6937
Microsoft Windows 11 version 22H3 10.0.22631.6649
Microsoft Windows 11 Version 23H2 10.0.22631.6649
Microsoft Windows 11 Version 24H2 10.0.26100.7840
Microsoft Windows 11 Version 25H2 10.0.26200.7840
Microsoft Windows 11 version 26H1 10.0.28000.1575
Microsoft Windows Server 2016 10.0.14393.8868
Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.8868
Microsoft Windows Server 2019 10.0.17763.8389
Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.8389
Microsoft Windows Server 2022 10.0.20348.4773
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2149
Microsoft Windows Server 2025 10.0.26100.32370
Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.32370

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21247 advisory

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 8 mo ago (2026-02-11)

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.3	CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA	3.1	7.3	CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

Affected products

Microsoft Windows 10 Version 1607
Microsoft Windows 10 Version 1809
Microsoft Windows 10 Version 21H2
Microsoft Windows 10 Version 22H2
Microsoft Windows 11 version 22H3
Microsoft Windows 11 Version 23H2
Microsoft Windows 11 Version 24H2
Microsoft Windows 11 Version 25H2
Microsoft Windows 11 version 26H1
Microsoft Windows Server 2016
Microsoft Windows Server 2016 (Server Core installation)
Microsoft Windows Server 2019
Microsoft Windows Server 2019 (Server Core installation)
Microsoft Windows Server 2022
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation)
Microsoft Windows Server 2025
Microsoft Windows Server 2025 (Server Core installation)

Classification

Weakness

CWE-20 Improper Input Validation
CWE-122 Heap-based Buffer Overflow
CWE-125 Out-of-bounds Read

References

msrc.microsoft.com /update-guide/vulnerability/CVE-2026-21247
vendor-advisory, patch

Sources

CVE List CVE-2026-21247
NVD CVE-2026-21247

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary