Description

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

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.0",
  "pubDate": "2026-08-11T17:18:56.920Z",
  "pubdate": "2026-08-11T17:18:56.920Z",
  "executiveSummary": "This vulnerability is classified as a Use-After-Free (UAF) memory corruption flaw residing within the Windows Win32K component. The primary impact of successful exploitation is local privilege escalation (LPE), allowing an authorized threat actor to execute arbitrary code with elevated system privileges.\nThe affected product is the Microsoft Windows operating system, specifically targeting the kernel-mode Win32K subsystem which handles window management, user interface controls, and graphics device interface operations. The risk implications are severe, as an attacker who has achieved initial code execution within a low-privilege context can compromise the entire underlying operating system kernel, bypassing standard security boundaries and access controls.\nThe required attacker capabilities involve local access to the target system and an existing execution context. The exploitation requirements dictate that the attacker must already be authenticated and authorized to execute code locally on the machine, typically via a standard user account or a restricted process. No network exposure is required, as the attack surface is strictly local to the Windows kernel interface exposed by Win32K.",
  "technicalDetails": "The vulnerability stems from improper memory management within the Windows Win32K kernel-mode driver, specifically leading to a Use-After-Free condition. A Use-After-Free vulnerability occurs when a program continues to use a pointer after the memory region it references has been deallocated or freed. If the application does not clear or nullify the pointer reference after the deallocation (resulting in a dangling pointer), subsequent operations attempting to access the object interact with unmanaged or reallocated memory.\nThe vulnerable component is the Win32K subsystem responsible for processing specific window objects, system messages, or graphical structures. When specific API sequences are invoked by a local process, the kernel allocates memory for a given data structure. Under precise timing conditions or specific operational states, the object is prematurely freed while a reference to the same memory address remains active within another kernel execution thread or data structure.\nThe attack flow proceeds as follows: First, the local attacker initializes interaction with the Win32K subsystem through standard user-mode graphical or windowing system APIs. Second, the attacker crafts a sequence of operations designed to allocate a target kernel object and subsequently trigger its premature deallocation while retaining a dangling pointer reference. Third, the attacker performs heap manipulation or grooming techniques to force the kernel allocator to reuse the newly freed memory region with attacker-controlled data, effectively overlapping a crafted structure with the original dangling pointer reference.\nWhen the Win32K component subsequently accesses the dangling pointer, it processes the attacker-controlled data as if it were the original legitimate kernel object. This type confusion and memory corruption primitive allows the adversary to manipulate kernel pointers, function pointers, or critical control data structures.\nThe authentication requirements are low, as the attacker must be locally authenticated, but no administrative privileges are required prior to exploitation. The privilege requirements specify that the attacker needs local execution capabilities on the host system. The network exposure is zero, as the vulnerability cannot be triggered remotely and relies entirely on local system calls to the Win32K driver.\nThe payload behavior resulting from successful exploitation involves executing arbitrary code within ring 0 (kernel mode). The post-exploitation impact includes complete system compromise, disabling of security monitoring tools, installation of persistent kernel-mode rootkits, and total bypass of operating system security controls."
}