CVE-2026-88106 in Windows
Summary
by MITRE • 10/14/2026
Use after free in Windows Cloud Files Mini Filter Driver allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified as a use-after-free condition within the Windows Cloud Files Mini Filter Driver represents a critical security flaw that compromises the integrity of the operating system's kernel-level memory management. This specific driver is responsible for intercepting file I/O operations and managing interactions between local storage systems and cloud-based storage providers, such as OneDrive or other synchronized directories. The core technical issue arises from improper handling of object lifecycles within the driver’s codebase. Specifically, when a request to access or modify files in a cloud-synced directory is processed, the driver allocates memory structures to handle these operations. However, under certain race conditions or specific sequence of events involving rapid file creation and deletion, the driver fails to properly nullify pointers after freeing the associated memory blocks. This oversight results in dangling pointers that continue to reference deallocated memory regions.
When an authorized attacker exploits this flaw, they can manipulate the state of these freed memory structures through carefully crafted inputs or timing attacks. By writing controlled data into the previously allocated but now free memory space before it is reallocated for another purpose, the attacker gains the ability to overwrite critical kernel data structures. This manipulation allows the execution of arbitrary code within the context of the operating system’s most privileged process, typically SYSTEM level access. The exploitation path relies on precise timing and knowledge of internal driver mechanics, making it a sophisticated local privilege escalation vector that bypasses standard user-mode security boundaries.
The operational impact of this vulnerability is severe, as successful exploitation grants an attacker full control over the affected Windows host. With elevated privileges, malicious actors can install persistent backdoors, dump sensitive credentials stored in memory such as NTLM hashes or Kerberos tickets, modify system configurations to disable security features like Defender or firewalls, and move laterally across a network with undetected access. This capability effectively neutralizes many perimeter defenses since the attacker operates from within the trusted kernel space, making detection significantly more challenging for endpoint protection solutions that rely on user-mode monitoring.
Mitigation strategies primarily focus on applying vendor-supplied security updates that patch the underlying memory management logic in the Cloud Files Mini Filter Driver. Organizations should prioritize deploying these patches across all endpoints to eliminate the root cause of the vulnerability. In environments where immediate patching is not feasible, network segmentation and strict application whitelisting can help limit the potential impact by restricting which processes are allowed to interact with cloud-synced directories or execute code in sensitive areas of the file system. Additionally, enabling advanced auditing features for kernel-mode driver loading and memory access patterns may aid in detecting exploitation attempts before they result in full compromise.
From a classification perspective, this vulnerability aligns with CWE-416, Use After Free, which describes errors where software continues to use a pointer after it has been freed, leading to undefined behavior that can be exploited for code execution. In the context of the MITRE ATT&CK framework, this flaw facilitates techniques associated with Tactic 0003: Persistence and Tactic 0004: Privilege Escalation, specifically leveraging local exploits for privilege escalation such as those categorized under T1068. The exploitation requires local access initially, meaning that physical security or initial compromise of a user account is often the prerequisite step before this vulnerability can be leveraged to achieve administrative control over the system.