dbcve.org
Windows 10 1507Operating system · Microsoft

CVE-2025-21420

HIGH · 7.8 CVSS v3.1 Published 2025-02-11
Fix available
A fix is available. Upgrade to 10.0.10240.20915 / 10.0.14393.7785 or later.
See remediation →
80/100
Remediation priority · High
Zero-click Patch available

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
Windows Disk Cleanup Tool Elevation of Privilege Vulnerability

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
How this class of weakness works · CWE-59

A file operation follows a symbolic link without checking where it actually points, so an attacker who can plant or swap a link redirects the operation to a file they should not be able to touch. It is a common local privilege-escalation primitive. Remediation is resolving and validating the real target path, and avoiding operations on attacker-controllable links.

General guidance for the link following (symlink) class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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:< 10.0.10240.20915
Windows 10 1607Operating system
Affected:< 10.0.14393.7785
Windows 10 1809Operating system
Affected:< 10.0.17763.6893
Windows 10 21h2Operating system
Affected:< 10.0.19044.5487
Windows 10 22h2Operating system
Affected:< 10.0.19045.5487
Windows 11 22h2Operating system
Affected:< 10.0.22621.4890
Windows 11 23h2Operating system
Affected:<= 10.0.22631.4890
Windows 11 24h2Operating system
Affected:< 10.0.26100.3194

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

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 10.0.10240.20915 / 10.0.14393.7785 / 10.0.17763.6893 or later
Fixed in 10.0.10240.2091510.0.14393.778510.0.17763.6893
Vendor patch msrc.microsoft.com →
Recommended fix High confidence

Install the February 2025 or later Windows Security Update (KB5055527 or subsequent) appropriate for your Windows version: Windows 10 1507 build 10.0.10240.20915, Windows 10 1607 build 10.0.14393.7785, Windows 10 1809 build 10.0.17763.6893, Windows 10 21h2 build 10.0.19044.5487, Windows 10 22h2 buil

  1. 1. Open Windows Settings and navigate to Update & Security > Windows Update
  2. 2. Click 'Check for updates' to ensure you have the latest security patches
  3. 3. Install any available updates for your Windows version
  4. 4. Alternatively, download the security update from Microsoft Catalog: https://catalog.update.microsoft.com/ and search for CVE-2025-21420
  5. 5. After installation, restart the system to complete the patch
  6. 6. Verify the update was installed by checking Windows Update history
Caveat Standard Windows security update with no expected breaking changes; applies to all affected versions

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

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,950. Get the upgrade done

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-2025-21420 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