Description

Heap-based buffer overflow in Windows Cloud Files Mini Filter Driver allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:21.530Z",
  "pubdate": "2026-08-11T17:18:21.530Z",
  "executiveSummary": "A heap-based buffer overflow vulnerability exists within the Windows Cloud Files Mini Filter Driver, presenting a significant security risk to local environments.\nThe vulnerability allows an authorized local attacker to achieve local privilege escalation by exploiting improper memory handling within the affected driver.\nSuccessful exploitation of this flaw can grant the attacker elevated system privileges, potentially compromising the integrity and confidentiality of the entire operating system.\nThe affected product is the Windows Cloud Files Mini Filter Driver, which manages cloud file synchronization and virtualization services in the Windows operating system architecture.\nExploitation requires the attacker to have prior local access and authorization to interact with the target system, meaning unauthenticated remote attackers cannot exploit this vulnerability directly over a network.\nRisk implications are critical due to the potential for complete system compromise resulting from local privilege escalation, necessitating prompt remediation when patches are available from the vendor.",
  "technicalDetails": "The vulnerability is fundamentally a heap-based buffer overflow residing in the Windows Cloud Files Mini Filter Driver.\nThe root cause stems from insufficient boundary checks and improper validation of input data sizes when allocating and writing data to heap memory buffers managed by the driver.\nThe vulnerable component is the kernel-mode driver responsible for handling cloud file operations and filter communications.\nPrivilege requirements dictate that an attacker must possess local execution capabilities and authorization to interact with the driver interface.\nAuthentication requirements are limited to local system access, as the attack vector is strictly local and cannot be leveraged remotely due to the lack of network exposure.\nThe attack flow begins with the local attacker crafting a malicious payload designed to interact with the Windows Cloud Files Mini Filter Driver via IOCTLs (Input/Output Control codes) or standard file system filter communication channels.\nDuring the interaction, the attacker supplies oversized or malformed input data that exceeds the allocated heap buffer size defined by the driver.\nBecause the driver fails to properly validate the length of the incoming data against the destination heap buffer dimensions, a memory corruption condition occurs.\nThe excess data overflows the heap-based buffer, overwriting adjacent heap metadata or critical kernel structures residing in memory.\nBy meticulously engineering the overflow payload, the attacker can hijack execution flow, manipulate kernel objects, or overwrite function pointers.\nPost-exploitation impact includes the execution of arbitrary code with kernel-level privileges, effectively bypassing standard operating system security controls, disabling security software, and achieving full administrative control over the compromised Windows system."
}