EUVD-2026-43831
GHSA-vxv7-4qqv-8vf6
Severity by source
AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Requires existing low-privileged local access (AV:L/PR:L), no interaction, and reliably escalates across the service scope boundary (S:C) to full SYSTEM impact (C:H/I:H/A:H).
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Improper access control in Windows MIDI Service Module allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows MIDI Service Module on Windows 11 (versions 24H2, 25H2, and 26H1) lets an already-authenticated local user gain elevated privileges by abusing improper access control (CWE-284). Because the CVSS scope is changed (S:C), a successful attack breaks out of the service's context to compromise confidentiality, integrity, and availability of the broader system, effectively yielding SYSTEM-level control. Microsoft has released a patch; there is no public exploit identified at time of analysis and it is not listed in CISA KEV.
Technical ContextAI
The flaw resides in the Windows MIDI Service Module, a Windows 11 component responsible for Musical Instrument Digital Interface device and I/O handling introduced in the modern Windows Media/MIDI 2.0 stack. The root cause is CWE-284 (Improper Access Control): the service fails to correctly enforce authorization boundaries on a resource or operation it exposes, allowing a lower-privileged caller to invoke functionality or manipulate objects that should be restricted. The CPE data scopes this to Microsoft Windows 11 version 24H2, 25H2, and 26H1 (cpe:2.3:a:microsoft:windows_11_version_24h2/25h2/26h1). The changed scope in the CVSS vector indicates the vulnerable service runs at higher privilege than the attacker and the exploit crosses that trust boundary to affect the operating system as a whole.
RemediationAI
Apply the Microsoft security update for CVE-2026-50342 via the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50342; a patch is available per the vendor advisory, so deploy the current cumulative update for your Windows 11 branch (24H2, 25H2, or 26H1) through Windows Update or WSUS/Intune as the primary and complete fix. The exact fixed build number is published in the MSRC update guide and should be taken from there rather than assumed. Because this is a local EoP with no documented standalone workaround, the compensating controls if patching is delayed are to reduce local attack surface: enforce least-privilege so untrusted users cannot obtain interactive or standard-account access to affected hosts, and apply application allow-listing (WDAC/AppLocker) and EDR monitoring to detect anomalous processes interacting with the MIDI service - with the trade-off that these controls raise the bar but do not eliminate the underlying access-control flaw. Disabling MIDI functionality is not a documented vendor mitigation and could break audio/MIDI device workflows, so patching remains the only reliable remediation.
More in Windows 11 Version 24H2
View allRemote code execution in Windows IKE Extension (Internet Key Exchange) via double free memory corruption allows unauthen
Windows Shell protection mechanism failure (CVE-2026-32202) allows remote attackers to perform spoofing attacks over a n
Local privilege escalation in the Microsoft Windows Kernel allows an unauthorized attacker to gain elevated (SYSTEM-leve
Local privilege escalation in the Windows Kernel lets an already-authenticated attacker corrupt kernel memory via a use-
Local code execution in the Windows DHCP Client service stems from a use-after-free (CWE-416) memory-corruption flaw aff
Local privilege escalation in the Microsoft Windows Kernel allows an already-authenticated attacker to elevate to SYSTEM
Local code execution in the Windows Media component of supported Windows 10, Windows 11, and Windows Server (2016 throug
Local privilege escalation via heap-based buffer overflow in the Windows Message Queuing (MSMQ) Queue Manager component
Local privilege escalation in Microsoft Windows Win32K lets an authenticated low-privileged user corrupt kernel heap mem
Local privilege escalation in the Windows NTFS file system driver lets an authenticated low-privileged user win a race c
Elevation of privilege in the Windows Hyper-V virtual network switch (VMSwitch) lets an authenticated attacker operating
Remote code execution in Microsoft Windows Remote Desktop (RDP) allows an unauthorized network attacker to run arbitrary
Same weakness CWE-284 – Improper Access Control
View allSame technique Authentication Bypass
View allShare
External POC / Exploit Code
Leaving vuln.today