Description

Out-of-bounds read in Windows Win32K allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:38.200Z",
  "pubdate": "2026-08-11T17:18:38.200Z",
  "executiveSummary": "This vulnerability is classified as an out-of-bounds read affecting the Windows Win32K component.\nSuccessful exploitation of this flaw allows an authorized local attacker to elevate privileges on target systems.\nThe affected product is Microsoft Windows, specifically within the kernel-mode driver responsible for the Win32 subsystem graphical user interface and window management.\nThe risk implications include unauthorized access escalation, potentially allowing a low-privileged user to execute arbitrary code with elevated system or administrative privileges.\nAttacker capabilities are constrained by the requirement of local access, meaning the adversary must already possess execution capabilities on the host system.\nExploitation requirements include prior authorization to run code locally and the ability to interact with the Win32K subsystem interface to trigger the memory read condition.",
  "technicalDetails": "The vulnerability resides within the Windows Win32K kernel-mode driver, specifically in the handling of internal data structures where bounds checking is improperly enforced.\nThe root cause is an out-of-bounds read condition, occurring when the software reads data past the end of the intended buffer or memory allocation.\nThe vulnerable component is the Win32K subsystem, which executes in kernel mode and handles window management, user input processing, and GDI rendering operations.\nAuthentication requirements dictate that the attacker must possess valid local credentials and be able to execute code within the user session.\nPrivilege requirements are minimal prior to exploitation, typically requiring standard user privileges to initialize the attack vector.\nNetwork exposure is non-existent, as the vulnerability requires local execution and cannot be exploited remotely over a network interface.\nThe step-by-step attack flow begins with the local attacker executing a specially crafted application or script designed to interact with specific Win32K system calls or APIs.\nDuring this interaction, the attacker supplies manipulated parameters that influence size or index calculations within the vulnerable function.\nDue to the absence of rigorous bounds validation, the component processes the request and reads memory adjacent to the legitimate buffer boundaries.\nThis out-of-bounds read operation may expose sensitive kernel memory contents, such as pointer addresses or system state information, to user mode.\nAn attacker can leverage the leaked kernel pointers or memory contents to defeat mitigation mechanisms such as Kernel Address Space Layout Randomization.\nPost-exploitation impact involves chaining this information disclosure with a secondary vulnerability or memory corruption flaw to achieve complete local privilege escalation to SYSTEM level."
}