CVE-2025-62221: Use after free in Windows Cloud Files Mini Filter Driver allows an authorized attacker to elevate privileges locally.

CVE-2025-62221 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2025-12-09

A security vulnerability exists in the Microsoft Windows component responsible for managing cloud-based files. An attacker who already has basic access to a system could exploit this flaw to gain full administrative control. This vulnerability has been observed being used in active attacks, making it a high priority for remediation to prevent unauthorized system takeovers.

Technologies: Microsoft Windows. Vendors: Microsoft.

Quick answers

Is CVE-2025-62221 exploited in the wild?
Yes. CVE-2025-62221 is known to be exploited in the wild, first recorded on 9 December 2025. Treat it as urgent.
How severe is CVE-2025-62221?
Critical severity, with a CVSS score of 7.8, published 9 December 2025.
Which products and versions are affected?
Microsoft Windows 10 1809, 21H2, 22H2; Microsoft Windows 11 23H2, 24H2, 25H2; Microsoft Windows Server 2019, 2022, 23H2, 2025.
Is there a fix for CVE-2025-62221?
A patch was published on 2025-12-09. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2025-62221 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2025-62221?
Check whether you run Microsoft Windows. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A use-after-free (UAF) vulnerability (CWE-416) exists in the Windows Cloud Files Mini Filter Driver (cldflt.sys). The flaw is triggered when the driver improperly handles objects in memory, allowing a locally authenticated attacker with low privileges to execute code with elevated system permissions. The attack vector is local, requiring no user interaction. This vulnerability is confirmed to be exploited in the wild and affects multiple versions of Windows 10, 11, and Windows Server. Microsoft has released security updates to address this issue.

Affected products

  • Microsoft Windows 10 1809, 21H2, 22H2
  • Microsoft Windows 11 23H2, 24H2, 25H2
  • Microsoft Windows Server 2019, 2022, 23H2, 2025

Timeline

  • 2025-12-09: disclosed
  • 2025-12-09: advisory
  • 2025-12-09: kev added: Added to CISA KEV catalog due to active exploitation.
  • 2025-12-09: patched

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