Windows Cloud Files Mini Filter Driver Privilege Escalation (CVE-2025-62221)

Historical catalog analysis: CISA added this entry on December 09, 2025. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.

What the vulnerability is

CVE-2025-62221 is a Use After Free (CWE-416) vulnerability located within the Microsoft Windows Cloud Files Mini Filter Driver. This flaw can be leveraged by an attacker who already possesses authorized access to the system to elevate their privileges locally.

Exposure and applicability

This vulnerability specifically affects Windows systems utilizing the Cloud Files Mini Filter Driver. Because this driver is integral to how certain cloud-integrated file systems operate within Windows, exposure is tied to the presence and activity of this specific component rather than a general OS version alone. Organizations managing hybrid cloud environments or those deploying Windows endpoints with integrated cloud storage services are most likely to be affected.

Remediation priorities

Based on our analysis, vulnerability management teams should prioritize remediation based on the level of local access granted to non-administrative users on critical systems.

1. Identify Affected Assets: Inventory all Windows endpoints and servers to determine where the Cloud Files Mini Filter Driver is active.
2. Apply Vendor Mitigations: Deploy the specific updates or mitigations provided by Microsoft for CVE-2025-62221.
3. Cloud Service Alignment: For organizations utilizing cloud services, align remediation efforts with BOD 22-01 guidance to ensure consistent exposure reduction across managed environments.
4. Decommissioning: In scenarios where mitigations cannot be applied or verified, the source suggests discontinuing use of the affected product as a final risk reduction measure.

How to validate remediation

Verification must move beyond simple version checks. While confirming that a patch has been deployed is a necessary first step, it does not inherently prove that the vulnerability is mitigated in the active runtime environment.

Defenders should verify that the Cloud Files Mini Filter Driver is operating under the updated, patched version and that the mitigation is active across all targeted assets. Validation evidence should include deployment logs from centralized patch management systems cross-referenced with system-level verification of the driver’s current state. The goal is to confirm a verified result—that the specific use-after-free condition is no longer present in the running driver.

Limits and open questions

There are several unknowns regarding this vulnerability. It is currently unknown whether this flaw has been utilized in known ransomware campaigns. Additionally, while CISA has established a remediation deadline of December 30, 2025, for federal agencies, this date serves as a risk benchmark rather than a legal requirement for private sector organizations.

Residual risk remains if the driver is updated but other local vectors allow an attacker to bypass existing security boundaries. Because this is a local privilege escalation flaw, it assumes the attacker has already gained initial access; therefore, patching this vulnerability reduces the impact of a compromise but does not prevent the initial entry.

Source and editorial note

CVE-2025-62221: Microsoft Windows Use After Free Vulnerability · Source date: December 09, 2025 · Retrieved August 31, 2026.

Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.

Archive date: December 12, 2025. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: September 26, 2026 at 01:29 UTC.

Request a Vulnerability Assessment