Description

Untrusted pointer dereference in Windows GDI allows an authorized attacker to disclose information locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.5",
  "pubDate": "2026-08-11T17:18:10.880Z",
  "pubdate": "2026-08-11T17:18:10.880Z",
  "executiveSummary": "An information disclosure vulnerability exists within the Windows Graphics Device Interface (GDI) component, specifically stemming from an untrusted pointer dereference condition. This security flaw allows an authenticated local attacker to read sensitive memory contents, potentially facilitating the bypass of downstream security mitigations such as Address Space Layout Randomization (ASLR).\nThe affected product is the Windows operating system, specifically targeting the GDI subsystem responsible for representing graphical objects and transmitting them to output devices like monitors and printers. The risk implication centers on local reconnaissance and the unauthorized disclosure of protected kernel or user-space memory, which can be leveraged in more complex, multi-stage exploitation chains.\nExploitation requirements dictate that the threat actor must already possess local access to the target system and execute malicious code under standard user privileges. The vulnerability does not provide remote code execution capabilities or direct privilege escalation on its own, but rather serves as an information leak primitive. Interaction with the vulnerable GDI subsystem via specially crafted system calls or application logic is required to trigger the unsafe pointer dereference and extract the resulting data.",
  "technicalDetails": "The root cause of this vulnerability lies in the improper validation and handling of pointers within the Windows GDI kernel-mode driver or user-mode rendering components. When processing specific graphical commands or data structures, the subsystem dereferences an untrusted pointer without properly verifying its boundaries, origin, or type safety. This lack of rigorous input validation and pointer sanitation leads directly to memory exposure conditions.\nThe vulnerable component is the Windows GDI graphics engine, which handles core drawing services, device contexts, and graphical primitives. Because GDI operates extensively within both user and kernel contexts to optimize rendering performance, memory handling errors in this subsystem often create significant security boundaries issues. The affected versions encompass the standard builds of the Microsoft Windows operating system where the unpatched GDI component resides.\nRegarding authentication and privilege requirements, the attack must be performed locally. The adversary requires valid execution privileges on the host system to interact directly with the GDI application programming interfaces. Network exposure is not a factor, as the vulnerability cannot be exploited remotely over a network protocol. The attack vector is strictly local, executed through user-mode applications invoking specific graphical functions that interact with the flawed driver logic.\nThe step-by-step attack flow proceeds as follows: First, the authenticated attacker establishes execution context on the target Windows system, typically via a standard user account or a compromised low-privilege process. Second, the attacker initializes a malicious routine or custom application designed to interface with the Windows GDI subsystem. Third, the application crafts and submits a sequence of specialized graphical requests or manipulated data structures intended to interact with the vulnerable pointer handling routines. Fourth, the GDI component processes the input and attempts to dereference the untrusted pointer without conducting adequate validation checks. Fifth, due to the absence of bounds and validity verification, the system reads memory locations outside the intended allocations, returning the contents back to the attacker-controlled process. Finally, the attacker captures the leaked memory data, analyzing it for sensitive pointers, cryptographic keys, or structural offsets necessary to defeat memory randomization defenses."
}