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": "2026-08-11T17:18:21.157Z",
  "pubdate": "2026-08-11T17:18:21.157Z",
  "executiveSummary": "This vulnerability is classified as a Use After Free (UAF) memory corruption flaw residing within the Windows Win32K component.\nSuccessful exploitation of this security defect allows an authorized local attacker to execute arbitrary code within kernel space, resulting in local privilege escalation (LPE) to SYSTEM level privileges.\nThe affected system component is the Windows kernel-mode graphics driver subsystem (Win32K).\nThe risk implication is severe, as an authenticated low-privileged user can compromise the entire operating system kernel, bypass security boundaries, install malicious drivers, access sensitive data, or modify system-wide configurations.\nAttacker capabilities are strictly constrained to local access, requiring the execution of a crafted payload on the target machine.\nThe primary exploitation requirement is that the attacker must already possess local execution privileges on the host system, typically achieved via standard user accounts or compromised initial access vectors.",
  "technicalDetails": "The vulnerability stems from improper lifetime management of kernel objects within the Win32K component.\nA Use After Free condition occurs when the application continues to reference a memory address after it has been freed or deallocated, often due to dangling pointers remaining in memory structures after an object's destructor or cleanup routine has executed.\nIn the context of Win32K, this typically involves kernel-mode window objects, graphics device interface (GDI) objects, or user interface hooks where incorrect reference counting or synchronization flaws allow an object to be released while concurrent execution threads still hold valid pointers to the memory location.\nThe attack flow begins with the local attacker executing a specially crafted application designed to interact with the vulnerable Win32K subsystem via system calls.\nThe attacker manipulates specific window states, user handles, or graphical resources to induce a state where a target kernel object is prematurely freed.\nSubsequent to the deallocation, the attacker performs heap feng-shui or memory grooming techniques to allocate arbitrary data into the recently freed heap chunk, effectively replacing the original Win32K object with controlled payload data.\nWhen the operating system or the Win32K component subsequently accesses the dangling pointer, it interacts with the attacker-controlled memory structure instead of the original valid object.\nThis leads to type confusion, arbitrary read/write primitives, or control flow hijacking within ring 0 (kernel mode).\nAuthentication requirements dictate that the attacker must possess local interactive or programmatic access to the host.\nPrivilege requirements are minimal, as standard unprivileged domain or local user accounts can initiate the vulnerable Win32K API calls.\nNetwork exposure is non-existent, as the vulnerability cannot be triggered remotely without prior local code execution.\nPost-exploitation impact includes complete compromise of the underlying operating system, allowing the attacker to bypass access control lists, disable endpoint detection and response (EDR) agents, persist in the kernel, and execute arbitrary privileged commands."
}