dbcve.org
Windows 10 1507Operating system · Microsoft

CVE-2025-27491

HIGH · 7.1 CVSS v3.1 Published 2025-04-08
Fix available
A fix is available. Upgrade to 10.0.10240.20978 / 10.0.14393.7969 or later.
See remediation →
75/100
Remediation priority · High
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Use after free in Windows Hyper-V allows an authorized attacker to execute code over a network.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

This is a use-after-free (UAF) vulnerability in Windows Hyper-V, Microsoft's hypervisor. The UAF flaw allows an authorized attacker to execute arbitrary code, potentially leading to VM escape or privilege escalation. The CVSS 7.1 indicates network-exploitable code execution with some complexity.

MitigationApply the relevant Microsoft security patch for Hyper-V when available. Limit authorization scope and network exposure to reduce attack surface.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Windows 10 1507Operating system
Affected:< 10.0.10240.20978
Windows 10 1607Operating system
Affected:< 10.0.14393.7969
Windows 10 1809Operating system
Affected:< 10.0.17763.7136
Windows 10 21h2Operating system
Affected:< 10.0.19044.5737
Windows 10 22h2Operating system
Affected:< 10.0.19045.5737
Windows 11 22h2Operating system
Affected:< 10.0.22621.5189
Windows 11 23h2Operating system
Affected:< 10.0.22631.5189
Windows 11 24h2Operating system
Affected:< 10.0.26100.3775

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Hyper-V is installed
    Run 'Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V' in PowerShell or check 'Hyper-V' in Windows Features. Alternatively, run 'systeminfo' and look for Hyper-V in the OS Configuration listing.
    Affected if Hyper-V is present on the system (the vulnerability only applies when Hyper-V is enabled)
  2. Check Windows version number
    Run 'winver' from the Run dialog, or run 'systeminfo' in Command Prompt and note the OS Version/build number. Alternatively, run 'Get-ComputerInfo | Select-Object WindowsVersion, OsVersion, OsBuildNumber' in PowerShell.
    Affected if The installed Windows build number falls below the vulnerable thresholds for your specific Windows release (see version ranges in CVE documentation)
  3. Confirm Hyper-V Hypervisor is running
    Run 'bcdedit /enum all' and look for hypervisorlaunchtype, or run 'msinfo64' and check if 'Hyper-V - Hypervisor' shows 'Yes'. Also check services: run 'Get-Service vmcompute, vmms' in PowerShell to verify Hyper-V services status.
    Affected if The Hyper-V hypervisor is actively running (not just installed but actually operational)
  4. Check Hyper-V version components
    Run 'Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -like "*Hyper-V*"}' to list installed Hyper-V components, or check the Hyper-V version via 'vmms' service properties in services.msc.
    Affected if Hyper-V components are present and the underlying Windows version matches the vulnerable version ranges

You are affected if Hyper-V is enabled/running AND your Windows build number is below the threshold specified for your Windows release version (10.0.10240.20978, 10.0.14393.7969, 10.0.17763.7136, 10.0.19044.5737, 10.0.19045.5737, 10.0.22621.5189, 10.0.22631.5189, or 10.0.26100.3775 depending on your Windows version).

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 10.0.10240.20978 / 10.0.14393.7969 / 10.0.17763.7136 or later
Fixed in 10.0.10240.2097810.0.14393.796910.0.17763.7136
Interim mitigation

Apply the relevant Microsoft security patch for Hyper-V when available. Limit authorization scope and network exposure to reduce attack surface.

Recommended fix High confidence

Upgrade to the minimum fixed build for your Windows version: Windows 10 1507 to 10.0.10240.20978, Windows 10 1607 to 10.0.14393.7969, Windows 10 1809 to 10.0.17763.7136, Windows 10 21h2 to 10.0.19044.5737, Windows 10 22h2 to 10.0.19045.5737, Windows 11 22h2 to 10.0.22621.5189, Windows 11 23h2 to 10.

  1. 1. Identify the current Windows version and build number by running 'winver' or 'systeminfo' in Command Prompt
  2. 2. Determine which Windows 10 or 11 version/branch is currently installed (e.g., 1507, 1607, 1809, 21h2, 22h2, or Windows 11 22h2/23h2/24h2)
  3. 3. Check if the current build number is below the fixed threshold for your version
  4. 4. If below the fixed version, apply Windows Updates: Open Settings > Update & Security > Windows Update, then click 'Check for updates'
  5. 5. Alternatively, manually download and install the specific Windows security update from Microsoft Update Catalog
  6. 6. For enterprise environments, deploy the update via Windows Server Update Services (WSUS) or Group Policy
  7. 7. After installation, restart the system to complete the update
  8. 8. Verify the fix by checking the installed build number matches or exceeds the fixed version for your Windows branch
Caveat Standard Windows update risks apply - ensure critical workloads are backed up and tested in a staging environment before deploying broadly

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows 10 1507 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-27491 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data