Description

Use after free in Windows Win32K allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:56.730Z",
  "pubdate": "2026-08-11T17:18:56.730Z",
  "executiveSummary": "A use-after-free vulnerability exists within the Windows Win32K component, posing significant security risks to affected Microsoft Windows operating systems. This vulnerability allows an authorized local attacker to execute arbitrary code within the context of the kernel, leading to a local privilege escalation. The security flaw stems from improper memory management within the kernel-mode driver, specifically failing to properly clear pointer references after memory deallocation. An attacker with local access and authorization to execute code on the target system can leverage this weakness to manipulate dangling pointers, corrupt kernel memory structures, and bypass standard operating system security controls. Successful exploitation requires the execution of a specially crafted payload locally, granting the adversary elevated privileges necessary to compromise the entire system. Due to the kernel-level execution context, the impact of this vulnerability is critical, potentially allowing complete system takeover, installation of unauthorized software, creation of new accounts with administrative privileges, and disabling of security telemetry or endpoint detection mechanisms. Mitigation relies on applying official security updates provided by the vendor as soon as they become available.",
  "technicalDetails": "The vulnerability resides in the Windows Win32K kernel-mode driver, specifically concerning the handling and lifecycle management of kernel objects in memory. The root cause is a classic use-after-free condition, where a memory resource is freed or deallocated while a reference to that same memory address persists elsewhere in the driver logic. When the application or driver subsequently attempts to access the object via the dangling pointer, undefined behavior occurs, which can be deterministically controlled by a sophisticated attacker.\nExploitation of this vulnerability requires an authenticated attacker to possess local access to the target system. The attack flow begins with the preparation of a user-mode application designed to interact with the vulnerable Win32K subsystem through specific system calls or graphical device interface operations. By inducing a sequence of events that forces the kernel to allocate, free, and subsequently reference the targeted memory object, the attacker creates a race condition or predictable memory state.\nOnce the target object is freed, the attacker rapidly re-allocates the freed heap memory with controlled payload data using heap feng shui techniques, replacing the original kernel object with attacker-controlled structures. When the kernel subsequently references the dangling pointer, it processes the attacker-controlled data as if it were the legitimate kernel object. This condition allows the manipulation of function pointers or critical control data structures within kernel space.\nThe successful execution of this payload leads directly to kernel-mode code execution, effectively bypassing User Account Control and sandbox restrictions. The post-exploitation impact includes unrestricted read and write capabilities across physical memory, the ability to disable security agents, tamper with kernel logs, and escalate the execution context to NT AUTHORITY\\SYSTEM. Network exposure is typically direct-local, requiring interactive logon or pre-existing code execution capability within a low-privilege container or user session."
}