CISA Warns of Windows Cloud Files Mini Filter 0-Day Vulnerability Exploited in Attacks

A critical alert regarding an active zero-day vulnerability affecting the Microsoft Windows Cloud Files Mini Filter Driver.

The vulnerability poses a significant risk to organizations running affected Windows systems and requires immediate remediation efforts.

CISA reports that the vulnerability, tracked as CVE-2025-62221, is a use-after-free flaw in the Windows Cloud Files Mini Filter Driver.

That allows authorized attackers to elevate their local privileges on compromised systems.

CISA Notes on Active Exploitation Flaw

CISA states that this type of vulnerability is particularly dangerous because it enables attackers who have gained initial access to escalate their privileges.

Achieve system-level control, potentially leading to complete system compromise.

CVE ID	Vulnerability Type	Affected Component	Attack Vector	CWE Reference
CVE-2025-62221	Use After Free	Windows Cloud Files Mini Filter Driver	Local Privilege Escalation	CWE-416

The use-after-free vulnerability class is a memory safety issue in which software attempts to access memory that has already been released.

Allowing attackers to execute arbitrary code with elevated privileges. Organizations must take immediate action to protect their infrastructure.

CISA recommends applying all available Microsoft mitigations as soon as possible. For agencies operating cloud services, strict adherence to BOD 22-01 guidance is mandatory.

Organizations unable to implement patches should discontinue use of affected systems until remediation is available.

Added this vulnerability to the CISA catalog on December 9, 2025, with a mandatory remediation deadline of December 30, 2025.

This compressed timeline reflects the severity and active exploitation of this flaw in the wild. This vulnerability affects organizations across all sectors relying on Windows systems.

The elevation of privileged capability makes this particularly concerning for enterprises where attackers could leverage initial compromise into a complete infrastructure takeover.

CISA urges Organizations to prioritize Windows system inventory and patch deployment. IT teams must monitor Microsoft security advisories for comprehensive guidance on patches.

Implement updates as soon as testing confirms compatibility with critical systems.

Network defenders should enhance monitoring for unusual privilege escalation attempts and suspicious process behavior on Windows systems.

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