Description

Out-of-bounds read in Windows Win32K allows an authorized attacker to disclose information locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.5",
  "pubDate": "2026-08-11T17:18:32.287Z",
  "pubdate": "2026-08-11T17:18:32.287Z",
  "executiveSummary": "An out-of-bounds read vulnerability exists within the Windows Win32K component, enabling an authorized local attacker to disclose sensitive system information. This vulnerability poses a localized security risk by potentially exposing memory contents that could aid in bypassing security mitigations, such as Address Space Layout Randomization (ASLR). The flaw resides in how the Win32K kernel-mode driver processes specific data structures, failing to perform adequate boundary validation before fulfilling read operations. Successful exploitation requires the attacker to have local access and authorization to execute code on the target system. While the vulnerability does not directly permit remote exploitation or arbitrary code execution, the unauthorized information disclosure significantly elevates the risk profile by facilitating advanced multi-stage attack chains. Remediation relies strictly on applying official vendor patches for the affected Windows operating system versions.",
  "technicalDetails": "The vulnerability is classified as an out-of-bounds read residing within the Windows Win32K kernel-mode driver, a core component responsible for handling the Graphical Device Interface (GDI) and window management. The root cause stems from insufficient bounds checking during the processing of specific graphics or window messages, where user-supplied indices or size parameters fail to be properly validated against the allocated buffer boundaries.\nExploitation of this vulnerability occurs locally through a sequence of interactions with the Win32K API. An authorized attacker crafts a malicious application or script designed to invoke specific system calls that interface directly with the vulnerable driver functions. By supplying manipulated parameters, the attacker forces the Win32K component to read memory addresses outside the legitimate boundaries of the intended data structure.\nThe attack flow proceeds as follows: First, the local process initializes graphics handles or window objects through standard Win32 system calls. Second, the attacker submits a specially crafted request containing out-of-range offsets or dimensions to the kernel driver. Third, the Win32K component attempts to retrieve data from the specified memory location without verifying whether the target address falls within the valid allocated buffer range. Finally, the out-of-bounds memory contents are returned to the caller, allowing the attacker to inspect kernel memory contents.\nThe affected component is the Win32K kernel-mode driver across supported Windows platforms. Authentication and privilege requirements mandate that the attacker possesses local interactive access with standard user privileges to execute the malicious payload. Because the vulnerability is confined to local operations, network exposure is non-existent unless combined with a separate remote access vector. The post-exploitation impact is strictly limited to information disclosure; however, leaking kernel memory structures undermines critical defensive primitives like ASLR, thereby assisting attackers in engineering reliable local privilege escalation exploits."
}