Description

Heap-based buffer overflow in Windows MIDI Service Module allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:18.397Z",
  "pubdate": "2026-08-11T17:18:18.397Z",
  "executiveSummary": "A heap-based buffer overflow vulnerability has been identified within the Windows MIDI Service Module. This security flaw enables a locally authenticated threat actor to execute arbitrary code and achieve local privilege escalation on targeted systems. The vulnerability resides in the core memory management handling of MIDI data structures within the Windows MIDI Service Module. Successful exploitation requires the attacker to have prior authorized local access to the system, meaning they must already possess a foothold with low privileges before initiating the attack sequence. Upon successful exploitation, the vulnerability compromises the confidentiality, integrity, and availability of the operating system by granting the attacker elevated privileges, potentially allowing complete system takeover or domain compromise if administrative credentials are ultimately targeted. Given the local attack vector, the risk is amplified in multi-user environments, shared workstations, or enterprise networks where unprivileged users can execute code locally. Defensive operations must prioritize identifying unpatched systems running the affected Windows MIDI Service Module and applying official vendor patches as soon as they become available to neutralize the threat.",
  "technicalDetails": "The vulnerability is classified as a heap-based buffer overflow stemming from improper bounds checking and memory allocation logic within the Windows MIDI Service Module. The root cause lies in how the vulnerable component processes malformed or oversized MIDI input data streams, failing to accurately calculate the required buffer size on the heap prior to memory write operations. When an attacker supplies a specially crafted sequence of MIDI messages, the service allocates a fixed-size heap buffer that is insufficient to contain the incoming payload. Subsequent copy operations or data writes overflow the boundaries of the allocated heap chunk, corrupting adjacent heap metadata, function pointers, or critical application data structures stored within the heap space. The attack flow begins with the local attacker authenticating to the target machine with standard, unprivileged user rights. The attacker then interacts with the Windows MIDI Service Module via local inter-process communication (IPC), system APIs, or direct service interfaces exposed by the module. By transmitting a maliciously structured payload designed to trigger the heap memory corruption, the attacker overwrites critical execution pointers. When the application subsequently attempts to execute the corrupted pointers, control flow is hijacked, allowing the execution of arbitrary shellcode or payloads injected into the process memory space. Because the Windows MIDI Service Module typically executes with elevated system or administrative privileges, successful control flow hijacking results in the immediate elevation of the attacker's process context to match those high privileges. Post-exploitation impact includes unrestricted access to system resources, bypass of local security controls, installation of persistent backdoors, and lateral movement across the enterprise network. The vulnerability requires local access, authenticates the user context prior to triggering, and does not require network exposure or user interaction beyond the execution of the exploit payload by the authorized local user."
}