CVE tracker / CVE-2025-27491

CVE-2025-27491

CVE-2025-27491 is the Windows Hyper-V Remote Code Execution Vulnerability. Microsoft rates it Critical, CVSS 7.1. It is not in CISA's Known Exploited Vulnerabilities catalog. Published April 8, 2025.

Risk summary

HighRemote Code Execution

7.1

CVSS v3 base

1.4%

EPSS: chance of exploitation in 30 days

High

Severity

Critical

Microsoft's rating

Less Likely

Microsoft: exploitation

In CISA KEV

Microsoft describes it: “Use after free in Windows Hyper-V allows an authorized attacker to execute code over a network.”

How to fix it

Microsoft lists 27 affected products and the update that fixes each:

KB5055518 · fixed build 10.0.19045.5737, 10.0.19044.5737
Windows 10 Version 22H2 for 32-bit Systems, Windows 10 Version 22H2 for ARM64-based Systems, Windows 10 Version 22H2 for x64-based Systems, Windows 10 Version 21H2 for x64-based Systems, Windows 10 Version 21H2 for ARM64-based Systems, and 1 more
KB5055519 · fixed build 10.0.17763.7136
Windows Server 2019 (Server Core installation), Windows Server 2019, Windows 10 Version 1809 for x64-based Systems, Windows 10 Version 1809 for 32-bit Systems
KB5055521 · fixed build 10.0.14393.7969
Windows Server 2016 (Server Core installation), Windows Server 2016, Windows 10 Version 1607 for x64-based Systems, Windows 10 Version 1607 for 32-bit Systems
KB5055523 · fixed build 10.0.26100.3775
Windows Server 2025, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 24H2 for ARM64-based Systems, Windows Server 2025 (Server Core installation)
KB5055526 · fixed build 10.0.20348.3453
Windows Server 2022 (Server Core installation), Windows Server 2022
KB5055527 · fixed build 10.0.25398.1551
Windows Server 2022, 23H2 Edition (Server Core installation)
KB5055528 · fixed build 10.0.22621.5189, 10.0.22631.5189
Windows 11 Version 22H2 for x64-based Systems, Windows 11 Version 22H2 for ARM64-based Systems, Windows 11 Version 23H2 for x64-based Systems, Windows 11 Version 23H2 for ARM64-based Systems
KB5055547 · fixed build 10.0.10240.20978
Windows 10 for x64-based Systems, Windows 10 for 32-bit Systems

What Microsoft changed

April 9, 2025: The security updates for Windows 10 for 32-bit Systems and Windows 10 for x64-based Systems are now available. See the Security Updates table for more information.
April 8, 2025: Information published.

Details

Weakness: CWE-416: Use After Free
Publicly disclosed (Microsoft): No
Exploited (Microsoft): No
Known exploited (CISA KEV): Not listed
Published: April 8, 2025
Last revised: April 9, 2025

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References

Microsoft Security Update Guide NVD CVE record CWE

From Microsoft, CISA, NVD and FIRST data; the Microsoft details were read when this page was opened. Check the references above before you act.