Description

Heap-based buffer overflow in Windows Key Guard allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:19:01.400Z",
  "pubdate": "2026-08-11T17:19:01.400Z",
  "executiveSummary": "This vulnerability is classified as a heap-based buffer overflow affecting Windows Key Guard. The security flaw allows an authenticated local attacker to achieve local privilege escalation by executing arbitrary code with elevated privileges on the target system. The primary risk implication is the potential compromise of the operating system integrity, enabling malicious actors to bypass standard security controls and execute administrative functions. Exploitation requires local system access and authorized interaction with the vulnerable component, meaning an attacker must already possess execution capabilities within the local environment before initiating the attack lifecycle. There is no indication of remote network exposure, limiting the threat vector strictly to local threat actors or compromised low-privileged user sessions.",
  "technicalDetails": "The root cause of the vulnerability stems from improper bounds checking during memory allocation and data copying operations within the heap memory space managed by Windows Key Guard. When processing specific inputs or control requests, the vulnerable component fails to adequately validate the size of the incoming data relative to the allocated heap buffer size, resulting in a heap-based buffer overflow condition. The affected component is the internal memory management routine handling input buffers within Windows Key Guard. Because the flaw resides within a privileged context, successful exploitation allows an attacker to overwrite adjacent heap metadata or critical data structures. The attack flow commences when a locally authenticated adversary crafts a malicious payload designed to exceed the intended buffer boundaries. Upon supplying this input to Windows Key Guard, the oversized data spills past the allocated heap chunk boundary, corrupting adjacent heap structures. By carefully manipulating the heap layout and payload contents, the attacker can hijack execution flow or tamper with critical function pointers and objects stored on the heap. Privilege requirements necessitate that the attacker operates locally with sufficient authorization to interact with the vulnerable application interface. Network exposure is non-existent, as the attack surface is constrained to local inter-process communication or API invocation mechanisms. Post-exploitation impact includes unauthorized privilege escalation, allowing the execution of arbitrary instructions in the security context of the elevated service. This grants the attacker expanded capabilities to compromise further system components, manipulate operating system resources, and maintain persistent control over the host environment."
}