EUVD-2026-44244
GHSA-8fq3-vhhq-4r52
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local EoP by an existing low-privileged user (AV:L, PR:L) with no interaction and low complexity; use-after-free in a system service yields full C/I/A impact.
Primary rating from Vendor (microsoft).
CVSS VectorNVD
Lifecycle Timeline
5DescriptionNVD
Use after free 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) allows an already-authenticated low-privileged user to elevate to higher privileges by triggering a use-after-free memory-corruption condition (CWE-416). Reported by Microsoft with a vendor patch already available; there is no public exploit identified at time of analysis and SSVC records exploitation status as none. EPSS is low at 0.25% (16th percentile), consistent with a locally-exploitable EoP that is not yet weaponized.
Technical ContextAI
The flaw resides in the Windows MIDI Service Module, the operating-system component that handles Musical Instrument Digital Interface (MIDI) device and message routing on Windows 11. The root cause is a use-after-free (CWE-416): a memory object is freed while a dangling reference to it is retained and subsequently dereferenced, letting an attacker who controls the reclaimed allocation corrupt memory and hijack control flow or data. Because the service runs with elevated system context, corrupting its freed objects can translate directly into privilege elevation. The CPE data scopes the issue precisely to Microsoft Windows 11 version 24H2, 25H2, and 26H1 (cpe:2.3:a:microsoft:windows_11_version_24h2 / _25h2 / _26h1).
RemediationAI
Vendor-released patch: apply the Microsoft cumulative update that raises the build to at least 10.0.26100.8875 (24H2), 10.0.26200.8875 (25H2), or 10.0.28000.2525 (26H1), per the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56187. Since this is delivered through the standard Windows monthly cumulative update, install the latest Patch Tuesday roll-up and reboot to remediate. No Microsoft-published standalone workaround exists for the MIDI Service Module; as compensating controls until patching completes, restrict interactive and low-privilege local logon on sensitive and shared hosts (limiting who can run the code needed to reach the service), and prioritize patching multi-user, kiosk, and shared endpoints where untrusted local accounts exist - with the trade-off that these access restrictions do not neutralize the flaw for legitimate local users and only reduce the population of potential attackers.
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Same weakness CWE-416 – Use After Free
View allSame technique Use After Free
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External POC / Exploit Code
Leaving vuln.today