Description

Use after free in Virtual Hard Disk (VHD) Miniport Driver allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.0",
  "pubDate": "2026-08-11T17:18:06.417Z",
  "pubdate": "2026-08-11T17:18:06.417Z",
  "executiveSummary": "A use-after-free vulnerability resides in the Virtual Hard Disk (VHD) Miniport Driver, allowing an authorized local attacker to achieve privilege escalation.\nThe vulnerability represents a critical flaw in memory management within kernel-mode components, specifically involving improper object lifecycle handling.\nSuccessful exploitation of this weakness enables a malicious actor with local access to execute arbitrary code in the context of a privileged security context, bypassing standard operating system access controls.\nThe affected product is the Virtual Hard Disk (VHD) Miniport Driver.\nRisk implications include full compromise of the local operating system, unauthorized data access, and potential persistence mechanisms established at the kernel level.\nAttack capabilities require local execution access and authorization to interact with the vulnerable driver, meaning an attacker must already possess an authenticated session on the target system prior to exploitation.",
  "technicalDetails": "The vulnerability is classified as a use-after-free condition within the Virtual Hard Disk (VHD) Miniport Driver, which operates in kernel mode.\nThe root cause stems from improper management of dynamic memory allocations, specifically where a memory buffer or kernel object is referenced after it has been deallocated or freed.\nThe vulnerable component is the driver's I/O control (IOCTL) or internal request handling routine, which fails to correctly synchronize object reference counts or nullify pointers post-free.\nAuthentication requirements dictate that the attacker must possess local interactive or programmatic access to the system.\nPrivilege requirements specify that the attacker must be authorized to communicate with the driver interface, though exploitation directly leads to elevation of privileges to a higher security tier, typically SYSTEM or kernel level.\nNetwork exposure is non-existent as the attack vector is strictly local, leveraging direct driver communication channels.\nThe step-by-step attack flow begins with the local attacker initializing communication handles with the Virtual Hard Disk (VHD) Miniport Driver.\nThe attacker then sends a specific sequence of crafted input control codes or I/O requests designed to allocate a target kernel object.\nSubsequently, the attacker triggers a condition that causes the driver to deallocate the underlying memory while retaining a dangling pointer to the freed memory region.\nThrough heap manipulation techniques, commonly referred to as heap spraying or grooming, the attacker allocates new data of a controlled size and content into the exact memory location previously occupied by the freed object.\nWhen the driver subsequently accesses the dangling pointer, it interacts with the attacker-controlled data instead of the original valid structure.\nThis improper dereference leads to control flow hijacking, allowing the execution of arbitrary kernel-mode shellcode or manipulation of kernel structures to disable security mitigations and elevate local privileges.\nPost-exploitation impact includes unrestricted administrative control over the host operating system, capability to tamper with system logs, installation of rootkits, and complete compromise of confidentiality, integrity, and availability."
}