dbcve.org
Windows 10 1507Operating system · Microsoft

CVE-2025-27727

HIGH · 7.8 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 →
80/100
Remediation priority · High
Zero-click

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
Improper link resolution before file access ('link following') in Windows Installer allows an authorized attacker to elevate privileges locally.

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 Time-of-Check to Time-of-Use (TOCTOU) vulnerability in Windows Installer where the application improperly resolves symbolic links before accessing files. A local attacker could manipulate the timing between when Windows Installer checks a file path and when it actually accesses that file, potentially overwriting or accessing privileged files to escalate their local privileges.

MitigationApply the Microsoft security update for CVE-2025-27727 when released. As an interim measure, restrict non-administrative users from creating symbolic links in directories used by Windows Installer operations.

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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. Check Windows build number
    Open Command Prompt or PowerShell and run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to obtain the full build version.
    Affected if The build number is lower than any of the following: 10.0.10240.20978 (Win10 1507), 10.0.14393.7969 (Win10 1607), 10.0.17763.7136 (Win10 1809), 10.0.19044.5737 (Win10 21h2), 10.0.19045.5737 (Win10 22h2), 10.0.22621.5189 (Win11 22h2), 10.0.22631.5189 (Win11 23h2), 10.0.26100.3775 (Win11 24h2).
  2. Confirm Windows Installer component is present
    Verify the Windows Installer service exists by checking 'msiexec.exe' is present in System32 (typically C:\Windows\System32\msiexec.exe) or run 'msiexec' in command prompt.
    Affected if Windows Installer (msiexec.exe) is installed and functional on the system.
  3. Identify Windows release version family
    Run 'winver' to see the specific Windows 10 release (such as 1507, 1607, 1809, 21h2, 22h2) or Windows 11 release (22h2, 23h2, 24h2).
    Affected if The system is running any of the affected Windows versions listed in the CVE and the build number is below the corresponding patched threshold.

The environment is affected if the installed Windows build number is lower than the patched threshold for its specific Windows release 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 Microsoft security update for CVE-2025-27727 when released. As an interim measure, restrict non-administrative users from creating symbolic links in directories used by Windows Installer operations.

Recommended fix High confidence

Windows 10 1507: 10.0.10240.20978 | Windows 10 1607: 10.0.14393.7969 | Windows 10 1809: 10.0.17763.7136 | Windows 10 21h2: 10.0.19044.5737 | Windows 10 22h2: 10.0.19045.5737 | Windows 11 22h2: 10.0.22621.5189 | Windows 11 23h2: 10.0.22631.5189 | Windows 11 24h2: 10.0.26100.3775

  1. Open Settings > Update & Security > Windows Update
  2. Click 'Check for updates' to download and install all available security updates
  3. After updates are installed, verify the OS build number matches or exceeds the fixed version for your Windows release by running 'winver' command
  4. Restart the system if prompted to complete the installation
  5. Confirm the installed version by checking the Windows Update history to ensure KBXXXXX (the corresponding security patch) is listed
Caveat Standard Windows update with no expected breaking changes; standard restart required

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

Fix this in Windows 10 1507 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2025-27727 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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